Industrial vehicle equipped with material handling work controller

ABSTRACT

A load handling operation control apparatus for an industrial vehicle, which has a load carrying apparatus provided movably on a vehicle body, is provided. A load carrying apparatus  2  is positioned with a load handling target  41, 42  according to its movement. A load handling control section  47  has a display device  28  and a detection device for detecting the position of the load handling target. A image control section  46  displays positioning information for supporting positioning of the load carrying apparatus  2  with respect to the load handling target  41, 42  on the display device  28  based on a positional detection result detected by the detection device.

TECHNICAL FIELD

[0001] The present invention relates to an industrial vehicle equippedwith a load handling operation control apparatus. Particularly, theinvention relates to an industrial vehicle equipped with a load handlingoperation control apparatus which assists a positioning work to positiona load carrying apparatus, such as a pallet, for example, by allowing apicked-up image of a work area of the load carrying apparatus, providedon an industrial vehicle, to be seen through the screen of display meansprovided in a driver's seat or the like.

BACKGROUND ART

[0002] Conventionally, this type of industrial vehicle, for example, aforklift, has a multi-level mast provided on its vehicle body, and acarriage having a load carrying apparatus (attachment), such as forks,is so provided as to be liftable along a mast. At the time of performinga load pickup work or load deposition work at a high place in a rack,for example, a driver operates a load handling lever (lift lever) toprotract or retract the multi-level mast by hydraulic driving to movethe forks upward along the mast to position the load carrying apparatusto a pallet in the rack or a shelf surface.

[0003] At this time, the driver must manipulate the load handling leverwhile checking with the eyes if the forks are positioned to holes in thepallet or a position above the shelf surface by looking up at a highplace (e.g., 3 to 6 meters) from below. It is however difficult todetermine if the forks and a pallet or the like are positioned with theeyes by looking up at a high place, and even a skilled person needs timefor this positioning, disadvantageously.

[0004] For example, U.S. Pat. No. 5,586,620 discloses an apparatus thatassists a positioning work of the forks at a high place by attaching acamera to the carriage, picking up the state of a rack, a pallet or thelike positioned in front of the forks and allowing the driver in thedriver's seat to see the picked-up image via the screen of a displaydevice. This apparatus can allow an image picked up by the camera to beseen via the screen of the display device.

[0005] However, it was necessary to finely position the forks withrespect to a load on the screen after roughly positioning the forks withrespect to the load while looking up at a high place. Because a mark tobe a target for positioning was not displayed on the screen, it tooktime to finely position the forks.

[0006] Further, there is an idea of calculating the position of a palletor a shelf portion through image processing and automatically positionthe forks with respect to a load handling target, such as a pallet orshelf portion as a target based on the image data of the work areapicked up by the camera. This case, however, raises the problem that itis not easy to see through the screen that the positioning of the forkshas been completed.

[0007] The present invention has been devised to overcome the problemsand aims at providing an industrial vehicle equipped with a loadhandling operation control apparatus which can reliably assist thepositioning of a load carrying apparatus through a screen by displayingor drawing positioning information for positioning the load carryingapparatus on the screen that shows a work area (load handling target) ofthe load carrying apparatus.

DISCLOSURE OF INVENTION

[0008] To achieve the object, according to a first mode of the presentinvention, there is provided a load handling operation control apparatusin an industrial vehicle, which is provided with a load carryingapparatus in a movable manner. The load carrying apparatus is positionedto a load handling target according to its movement. The load handlingoperation control apparatus has display means and detection means fordetecting a position of the load handling target. Display control meansdisplays positioning information for supporting positioning of the loadcarrying apparatus with respect to the load handling target on thedisplay means based on a position detection result detected by thedetection means.

[0009] According to a second mode of the present invention, there isprovided a load handling control apparatus in an industrial vehicle. Theload carrying apparatus control apparatus has a load carrying apparatuswhich is provided in a displaceable manner on a vehicle body of theindustrial vehicle for doing a load carrying operation; load detectionmeans for detecting whether or not there is a load placed on or held bythe load carrying apparatus and outputting a detection signal; decisionmeans for determining whether it is a load pickup work or a loaddeposition work based on the detection signal from the load detectionmeans; and control means for causing the load carrying apparatus to do aload pickup work or a load deposition work based on decision by thedecision means.

[0010] According to a third mode of the present invention, there isprovided a work mode switching apparatus for an industrial vehicle,which can do a predetermined work under automatic control andselectively set a plurality of work modes for that predetermined work.The apparatus has detection means for detecting a state of thepredetermined work at the time of doing that work under automaticcontrol; work mode setting means for selectively setting one work modefrom the plurality of work modes according to contents of thepredetermined work based on a detected value from the detection means;and switching means for manually switching the work mode set by the workmode setting means to another work mode.

[0011] According to a fourth mode of the present invention, there isprovided a load handling aiding notification apparatus in an industrialvehicle. The apparatus has a load carrying apparatus movably provided ona vehicle body for doing a load carrying work; detection means fordetecting a position of a load handling target beforehand before avehicle approaches the load handling target; calculation means forcalculating a positional relationship between the load handling targetand vehicle based on a result of detection by the detection means; andnotification means for notifying steering information for guiding thevehicle in such a way that the load handling target is caught by theload carrying apparatus based on a result of calculation by thecalculation means.

[0012] According to a fifth mode of the present invention, there isprovided a voice notification apparatus for an industrial vehicle. Theapparatus has a load carrying apparatus movably provided on a vehiclebody for doing a load carrying work; image pickup means for picking upan image of a load handling target at the time of a load handlingoperation by the load carrying apparatus; identification means foridentifying a sign to be a mark at the time of positioning the loadcarrying apparatus based on image data picked up by the image pickupmeans; detection means for detecting a position of the load carryingapparatus with respect to the sign based on a result of identificationby the identification means; display means for visually displaying theposition of the load carrying apparatus based on a result of detectionby the detection means; output means capable of outputting voices to adriver; and voice synthesizing means for, when a display state by thedisplay means is changed according to a change in the position of theload carrying apparatus with respect to the sign, causing the outputmeans to output sounds according to that change.

[0013] According to a sixth mode of the present invention, there isprovided a work view field aiding apparatus for an industrial vehiclecapable of doing a plurality of different works. The apparatus picks upa work image that supports a work view field of a driver at the time ofdoing each work and shows the driver that work image according to eachwork.

BRIEF DESCRIPTION OF DRAWINGS

[0014]FIG. 1 is a perspective view of a forklift according to a firstembodiment.

[0015]FIG. 2 is a plan view of an operation lever.

[0016]FIG. 3 is a perspective view showing a state of a load carryingwork with respect to a rack.

[0017]FIG. 4 is a block diagram showing the electrical structure of aload handling operation aiding apparatus.

[0018]FIG. 5 is a front view showing marks and templates.

[0019]FIG. 6(a) is a screen diagram for explaining a screen coordinatesystem and FIG. 6(b) is an explanatory diagram of a matching method.

[0020]FIG. 7 is an exemplary perspective view for explaining a realcoordinate system.

[0021]FIG. 8 is a plan view for explaining a coordinate system.

[0022]FIG. 9 is a correlation diagram showing the relationship betweenthe real coordinate system and the screen coordinate system.

[0023]FIG. 10 is an exemplary diagram for explaining positioningcontrol.

[0024]FIG. 11 is a block diagram illustrating the process of positioningcontrol.

[0025]FIG. 12 is a diagram for explaining a method of calculating adrawing position, and FIG. 12(a) and FIG. 12(b) are exemplary diagramsrespectively showing the real coordinate system and the screencoordinate system.

[0026]FIG. 13 shows screens in positioning control, and FIG. 13(a) is adiagram showing a screen with a moving target point mark displayed whileFIG. 13(b) is a diagram showing a screen after positioning ends.

[0027]FIG. 14 is a perspective view of a forklift according to a secondembodiment.

[0028]FIG. 15 is an exemplary partly front view of a load handlingapparatus with a camera fixed to a mast.

[0029]FIG. 16 is a block diagram showing the electrical structure of aload handling operation aiding apparatus.

[0030]FIG. 17 is a block diagram showing the electrical structure of aload handling operation aiding apparatus according to a thirdembodiment.

[0031]FIG. 18 is a front view showing marks and templates according to afourth embodiment.

[0032]FIG. 19 is a screen diagram for explaining a screen coordinatesystem according to the fourth embodiment.

[0033]FIG. 20 is a flowchart of a load carrying work determiningroutine.

[0034]FIG. 21(a) is a side view showing forks placed in a load pickupposition and FIG. 21(b) is a side view showing the forks placed in aload deposition position.

[0035]FIG. 22 is a plan view of a control panel of an automaticelevation unit according to a fifth embodiment.

[0036]FIG. 23 is a block diagram showing the electrical structure of theautomatic elevation unit according to the fifth embodiment.

[0037]FIG. 24 is a side view showing a state when a load carrying workis done with a forklift 1 equipped with a camera according to a sixthembodiment.

[0038]FIG. 25 is a perspective view of a driver's seat.

[0039]FIG. 26 is an electric circuit diagram of a forklift.

[0040]FIG. 27(a) is a diagram showing a screen coordinate system andFIG. 27(b) is a diagram showing a real coordinate system.

[0041]FIG. 28 is a diagram showing the screen of a display device at atime of a load pickup mode.

[0042]FIG. 29 is a diagram showing the screen of the display device at atime of a load deposition mode.

[0043]FIG. 30(a) is an explanatory diagram showing a work state at thetime of stocking (load deposition) with a forklift according to aseventh embodiment and FIG. 30(b) is an explanatory diagram showing awork state at the time of shipment (load pickup).

[0044]FIG. 31 is a plan view of a control panel.

[0045]FIG. 32 is an electric circuit diagram of a forklift according tothe seventh embodiment.

[0046]FIG. 33 is a diagram showing a screen on which a pull-overinstruction guide according to an eighth embodiment is displayed.

[0047]FIG. 34 is a diagram showing the state of the screen after theposition of a vehicle has been corrected.

[0048]FIG. 35 is a flowchart of an instruction displaying processroutine.

[0049] FIGS. 36(a) and (b) are explanatory diagrams showing acircumstance in which the position of a vehicle is corrected.

[0050]FIG. 37 is a flowchart of an instruction displaying processroutine according to a ninth embodiment.

[0051]FIG. 38 is a flowchart of an instruction displaying processroutine according to a tenth embodiment.

[0052] FIGS. 39(a), (b) and (c) are explanatory diagrams showing acircumstance in which the position of a vehicle is corrected accordingto a prior art corresponding to the eighth embodiment.

[0053]FIG. 40 is a perspective view of a multi lever according to aneleventh embodiment.

[0054]FIG. 41 is a side view of the multi lever.

[0055]FIG. 42 is an electric circuit diagram of a forklift.

[0056]FIG. 43(a) is a diagram showing the screen of a display devicebefore positioning of forks and FIG. 43(b) is a diagram showing thescreen after positioning.

[0057]FIG. 44 is a diagram showing the screen of the display device whena mark is not displayed.

[0058]FIG. 45 is a diagram showing the relationship between the state ofmark identification and sounds.

[0059]FIG. 46 is a schematic perspective view showing a forkliftequipped with a work view field aiding apparatus according to a twelfthembodiment.

[0060]FIG. 47 is a schematic perspective view showing the forklift withforks lifted down.

[0061]FIG. 48 is an exemplary diagram showing an image in front of avehicle.

[0062]FIG. 49(a) and FIG. 49(b) are exemplary diagrams showing forks anda camera for load handling at the time of a load pickup work and at thetime of a load deposition work.

[0063]FIG. 50 is an exemplary diagram showing an image in front of theforks at the time of a load pickup work.

[0064]FIG. 51 is an exemplary diagram showing an image in front of theforks at the time of a load deposition work.

[0065]FIG. 52 is an electric block diagram of a work view field aidingapparatus and a load handling control system.

[0066]FIG. 53 is a schematic perspective view showing a forkliftequipped with a work view field aiding apparatus according to athirteenth embodiment.

[0067]FIG. 54 is a partly schematic front view of forks and a mastincluding a work camera.

[0068]FIG. 55 is an exemplary side view showing the forks and the workcamera at the time of a load pickup work.

[0069]FIG. 56 is an electric block diagram of the work view field aidingapparatus.

[0070]FIG. 57 is a schematic side view showing a counterbalance typeforklift equipped with a work view field aiding apparatus according to afourteenth embodiment.

[0071]FIG. 58 is an electric block diagram of the work view field aidingapparatus.

[0072]FIG. 59 is a side view of a reach type forklift equipped with aconventional forward visibility improving apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

[0073] First Embodiment

[0074] The first embodiment of the present invention as embodied into aposition detecting apparatus for a forklift will be described below withreference to the drawings.

[0075] As shown in FIG. 1, a reach type forklift truck (hereinaftercalled forklift) 1 as an industrial vehicle does a load carrying workusing forks 2 as a load carrying apparatus. Left and right front wheels(driven wheels) are respectively attached to the distal end portions ofa pair of left and right reach legs 4 extending frontward from the frontportion of a vehicle body 3. A drive and steering wheel 6 as a rearwheel is driven by a drive motor 8 which is driven with a battery 7, asa power source, installed in the vehicle body 3. A driver operates theforklift 1 by steering the drive and steering wheel 6 by manipulating asteering wheel 10 while standing on a stand type driver's seat 9provided on the right-hand side of the rear portion of the vehicle body3.

[0076] A load handling apparatus 11 located on the front side of thevehicle body 3 is provided movable in a forward and backward directionalong the left and right reach legs 4 by a reach cylinder 12. The loadhandling apparatus 11 has a multi-level (three-level type in theembodiment) mast 13, a carriage 14 for load handling, a center liftcylinder 15A and a pair of left and right side lift cylinders 15B (onlyone shown). The mast 13 is a three-level mast comprising an outer mast13A, a middle mast 13B, and an inner mast 13C. The load handlingapparatus 11 according to this embodiment is of a telescopic type (fullfree type) whose mast 13 does not start protracting or retracting untilthe carriage 14 has reached the topmost position of the inner mast 13C.

[0077] The center lift cylinder 15A is provided upright on the bottomplate of the inner mast 13C, and the carriage 14 lifts up and down alongthe inner mast 13C by the driving of the center lift cylinder 15A. Theside lift cylinders 15B is provided upright at the back of the outermast 13A, and is driven with the carriage 14 placed at the topmost endof the inner mast 13C, and the driving causes the three-level masts 13A,13B and 13C to protract or retract. The forks 2 are lifted up to, forexample, a maximum height of about 6 meters.

[0078] The forklift 1 is provided with an aiding apparatus 20, whichsupports an operation of positioning the forks 2 at a high place (highlifting height range). The aiding apparatus 20 has a camera liftingapparatus 21, which is installed at the front center portion of thecarriage 14 in a state extending longitudinally. The camera liftingapparatus 21 has a lift type camera unit 23, which is retained in ahousing 22 attached to the front center portion of the carriage 14 insuch a way as to appear from below there.

[0079] The camera unit 23 is lifted up and down between a storageposition where it is stored in the housing 22 and a lift-down positionwhere it projects from the lower end of the housing 22. The camera unit23 incorporates a camera (e.g., CCD camera) 24 as image pickup means atits lower end portion, and an image pickup section 24A (lens section)24A picks up the image of a load carrying work area in front of theforks. An image pickup window 22A is formed in the front lower portionof the housing 22 so that the image of the load carrying work area canbe picked up by the camera 24 even at the storage position through theimage pickup window 22A. Therefore, the camera 24 can pick up the imagein front of the forks 2 at the two positions, the storage position andthe lift-down position. A side shifter 16 is attached to a lift bracket(not shown), liftably attached to the mast 13, in such a way as to bemovable in a left and right direction and the camera lifting apparatus21 is shifted leftward and rightward together with the forks 2 at thetime of side shifting.

[0080] A display device (liquid crystal display device (LCD)) 28 isattached to a roof 27 in such a way that a driver standing on thedriver's seat 9 sees it well. An image in front of the forks 2, pickedup by the camera 24 at the time of a load carrying work, is shown on thescreen of the display device 28.

[0081] An operation lever (multi lever) 31 shown in FIG. 2 is providedon an instrumental panel. The operation lever 31 singularly can ensureall the operations for the driving operation and load handlingoperation, and has a plurality of operation sections.

[0082] The operation lever 31 has a lever body 33 which tilts forwardand backward along a slot 32 formed on the instrumental panel. The leverbody 33 is held in the neutral position upright approximatelyperpendicular to the panel surface by the urging force of a spring (notshown) at a non-operational time. A grip 34 is attached to the upper endportion of the lever body 33 in such a way that it is tilted by an angleof about 30 degrees to 60 degrees to the vehicle's widthwise direction.

[0083] A knob 35 approximately cylindrical in shape is provided at theleft end portion of the grip 34 in such a way as to be rotatable aboutan axial line C. A seesaw switch 36 is provided on the left-hand sideportion of the grip 34, and a cross switch 37 is provided on the frontside of the grip 34 on the left-hand side portion, and an activationswitch 38 is provided at the back of the grip 34 on the left-hand sideportion. The grip 34 is used in a state in which it is gripped with theright hand of the driver putting the right elbow on the instrumentpanel. With the grip 34 gripped, the knob 35 and the cross switch 37 aremanipulated with a thumb, the seesaw switch 36 is manipulated with anindex finger and the activation switch 38 is manipulated with a middlefinger. The cross switch 37 as seen from an A direction is shown in acircle in the diagram.

[0084] Pushing and tilting the lever body 33 forward with the right handholding the grip 34 moves the forklift 1 forward and pulling and tiltingthe lever body 33 backward moves the forklift 1 backward. When the knob35 is turned upward by depressing a projection 35A formed on the knob 35upward with the thumb, the forks 2 are lifted upward, and when the knob35 is turned downward by pushing the projection 35A downward with thethumb, the forks 2 are lifted downward. Pushing the front end of theseesaw switch 36 with the index finger moves the load handling apparatus11 forward, and pushing the rear end of the seesaw switch 36 with theindex finger moves the load handling apparatus 11 backward. The crossswitch 37 is operable in four directions, up and down and left andright. The tilt of the mast 13 is operated in accordance with themanipulation of the cross switch 37 in the up and down direction and theside shift is operated in accordance with the manipulation in the leftand right direction. Pushing the upper end portion of the cross switch37 with the thumb tilts the mast 13 forward and pushing the lower endportion of the cross switch 37 with the thumb tilts the mast 13backward. Pushing the right end portion of the cross switch 37 with thethumb moves the forks 2 rightward and pushing the left end portion ofthe cross switch 37 moves the forks 2 leftward.

[0085] As shown in FIG. 3, in the present embodiment, a rack 40 and apallet 41 which are load handling targets are affixed with marks M1 andM2 that are targets at the time of positioning the forks 2 with respectto the rack 40 or the pallet 41. That is, the mark M1 for palletposition detection is affixed to the front and back sides of the pallet41 at the center portion between two insertion holes 41A. The mark M2for rack position detection is affixed to the center portion of thefront side of a shelf plate (beam) 42 of the rack 40. The mark M1affixed to the pallet 41 and the mark M2 affixed to the shelf plate 42are formed of figures with white and black patterns inverted to eachother. At the time of performing automatic fork positioning control toautomatically position the forks 2 to a load handling target, theamounts of sideway (Y direction) and vertical (Z direction) deviationsbetween the forks 2 and the load handling target (pallet 41 or the shelfplate 42) are computed from the position of the mark M1 (or M2) pickedup by the camera 24 on the screen, and the forks 2 are automaticallycontrolled to position in such a way as to cancel out the deviationamounts.

[0086] The electrical structure of a load handling operation aidingapparatus 20 will be described based on FIG. 4.

[0087] The load handling operation aiding apparatus 20 has a controller45. The controller 45 has an image control section 46, a load handlingcontrol section 47, drive circuits 48 and 49 and a solenoid drivecircuit 50.

[0088] The camera 24 is electrically connected to the input side of theimage control section 46 to which a video signal (image signal) isinput, and the display device 28 and a speaker 51 are connected to theoutput side. The image control section 46 displays a picked-up image onthe screen of the display device 28 based on the video signal (imagesignal) from the camera 24. The image control section 46 performs animage recognition process (template matching process) to recognize amark from the picked-up image and grasps the position of a load handlingtarget from the position of the mark on the screen (screen coordinatesystem) which is grasped by this image recognition. Then, a displayprocess for displaying a target moving point (target mark) to be atarget at the time of positioning the forks 2 in a position to catch theload handling target on the screen is performed.

[0089] In this display process, a method of displaying a target mark onthe screen of the display device 28 is used as a method for guiding atarget moving point. The display process will be described in detaillater. An aiding state for a load carrying work or the content of aninstruction or the like to a worker is announced in sounds from thespeaker 51.

[0090] Meanwhile, the load handling control section 47 is connected withan upper-limit position detection switch 52, a lower-limit positiondetection switch 53, individual potentiometers 54 and 55 and switches 36to 38 of the multi lever 31, a height sensor 58 as height detectingmeans, a load weight sensor 59, a tilt angle sensor 60, etc. The loadhandling control section 47 is connected with an electric actuator 61and load handling motor (electric motor) 62 as lifting drive means viathe drive circuits 48, 49 and with the solenoids of variouselectromagnetic proportional valves 65 to 69 attached to an oil controlvalve 64 via the solenoid drive circuit 50. The load handling controlsection 47 and the load weight sensor 59 constitute discriminationmeans.

[0091] Based on signals from the individual potentiometers 54 and 55 andswitches 36 and 37, the load handling control section 47 performscurrent value control of the electromagnetic proportional valves. 65 to69 and drive control of the load handling motor 62. When a load handlingpump (hydraulic pump) 70 is driven by the activation of the loadhandling motor 62, the hydraulic fluid is supplied to the oil controlvalve 65. Based on an operation signal from the multi lever 31, eachelectromagnetic proportional valve 65 to 69 corresponding to theoperation is subjected to proportional control by the load handlingcontrol section 47 and the lift cylinders 15A, 15B, the reach cylinder12, the side shift cylinder 71 and the tilt cylinder 72 arehydraulically controlled, so that the elevation operation, reachoperation, side shift operation and tilt operation of the forks 2 can beperformed. The cylinders 15A, 15B and 71 constitute drive means.

[0092] The load handling control section 47 performs lifting control ofthe camera unit 23 and automatic fork positioning control in addition tothe load carrying control at the time of operating the multi lever. Theautomatic fork positioning control, which is for supporting a loadcarrying work at a high place which is carried out with the forks 2lifted up to or higher than a given height, is executed only when theheight of the forks 2 detected by the height sensor 58 is equal to orhigher than a set height (e.g., about 2 meters). The load handlingcontrol section 47 discriminates a load handling mode by determiningwhether or not there is a load on the forks 2 based on the detectedvalue from the load weight sensor 59. In the “load pickup mode” wherethere is no load on the forks 2 and a load-weight detected value becomesequal to or smaller than a threshold value, the load handling controlsection 47 places the camera unit 23 in the storage position, while inthe “load deposition mode” where there is a load on the forks 2 and aload-weight detected value exceeds the threshold value, it places thecamera unit 23 in the lift-down position. The electric actuator 61 isdriven to lift the camera unit 23 up and down. The electric actuator 61is stopped when the camera unit 23 reaches the upper-limit position andthe upper-limit position detection switch 52 is switched on and when thecamera unit 23 reaches the lower-limit position and the lower-limitposition detection switch 53 is switched on.

[0093] The image control section 46 has a display processing section 75,an image processing section 76, a drawing display section 77, a drawingdata memory section 78 and a voice synthesizing section 79. The displayprocessing section 75 sends out a video signal input from the camera 24to the display device 28 in such a way that the image picked up by thecamera 24 is displayed on the screen. The voice synthesizing section 79performs voice synthesizing process for voice guidance or the like andoutputs a voice signal to the speaker 51. Image data from the displayprocessing section 75 is input to the image processing section 76. Thedrawing display section 77 and drawing data memory section 78 constitutedrawing control means.

[0094] The image processing section 76 performs an image recognitionprocess to compute the position of the mark M1, M2 on the screen andcomputes the positional relationship between the vehicle or forks 2 andthe load handling target based on the computed position of the mark M1,M2. The image processing section 76 has an image recognition processingsection 81, a template memory section 82, an image computing section 83and a display position determining section 84 as calculation means.

[0095] The image recognition processing section 81 performs an imagerecognition process by a pattern matching method. When the amount ofdeviation between the vehicle and the load handling target in thevehicle's widthwise direction exceeds an allowable range, the imagecomputing section 83 computes the pull-over direction and pull-overdistance needed to eliminate the deviation amount. The display positiondetermining section 84 determines a display position on the screen wherea display indicating the pull-over direction and pull-over distance isto be displayed. The image processing section 76 is constituted by amicrocomputer and program data stored in a memory (ROM) or the like. Thedrawing display section 77 and the drawing data memory section 78 areconstituted by a drawing control gate array and drawing VRAM. The imagerecognition processing section 81, the template memory section 82 andthe image computing section 83 constitute detection means and imagerecognition means.

[0096]FIG. 5 shows marks and templates. FIG. 5(a) shows the mark M1 forpallet position detection and FIG. 5(c) shows the mark M2 for rackposition detection. FIG. 5(b) shows the template T1 for the mark M1, andFIG. 5(d) shows the template T2 for the mark M2.

[0097] The mark M1 is constructed by arranging two patterns P1, P1, andthe mark M2 is constructed by arranging two patterns P2, P2. A markindicates the entire design, and a pattern indicates a repeating unit,which constitutes a mark. The templates T1 and T2 used in a patternmatching process have the same designs as the patterns P1 and P2. Thepatterns P1 and P2 have designs with the black and white inverted toeach other.

[0098] Each pattern P1, P2 has a design separated into white and blackcolors by a plurality of boundary lines extending radially around onepoint. Each pattern P1, P2 in the present embodiment has a designseparated into white and black colors by four areas defined by the twodiagonal lines of a square. Note that the contour line equivalent to thesides of the rectangular shape of the template is not a part of thedesign. The size of the mark M1, M2 to be displayed on the screen 28Achanges in accordance with the distance between the mark and the camera.Even in that case, however, a pattern of the same size as the templateT1, T2 always exists in the center portion of the picked-up patterns P1,P2, so that the mark M1, M2 can be recognized through pattern matchingusing only a single template T1, T2. The templates T1, T1 are set to apredetermined size such that all the marks M1, M2 picked up within apredetermined distance from the camera 24 can be identified. Thepredetermined size of the templates is the same size as or smaller thanthe size of the mark when an image is picked up at a predetermineddistance away.

[0099] Stored in the template memory section 82 shown in FIG. 4 is dataof the two templates T1 and T2. The image recognition processing section81 uses the template T1 when the load handling mode notified by the loadhandling control section 47 is the “load pickup mode” and uses thetemplate T2 when it is the “load deposition mode”. That is, when it isthe load pickup mode, a pattern matching process to identify the mark M1for pallet position detection is performed and when it is the loaddeposition mode, a pattern matching process to identify the mark M2 forrack position detection is performed.

[0100]FIG. 6(a) shows the screen coordinate system set on the screen. Inthe screen coordinate system, the coordinates are treated pixel bypixel, and the number of horizontal pixels H and the number of verticalpixels V are set on the screen 28A in FIG. 6(a). A description will begiven of the mark M2 as an example. The image recognition processingsection 81 performs matching with respect to the two patterns P2, P2constituting the mark M2 on image data at two locations using thetemplate T2 and recognizes each pattern P2, P2, as shown in FIG. 6(b).The image computing section 83 computes coordinates (I1, J1), (I2, J2)of the individual center points of the two patterns P2, P2 recognized bythe image recognition processing section 81 and acquires a barycenter(I, J) of the mark M2 and a center distance D between the patterns P2,P2 based on those two coordinate values. The same method of acquiringthe I, J and D values is applied for the mark M1.

[0101]FIG. 7 shows a real coordinate system. The real coordinate systemis assumed to be three-dimensional coordinates with the barycenter ofthe mark M as the origin O, the X axis taken in a directionperpendicular to the mark M and opposite to the camera 24, the Y axistaken in a direction rotated counterclockwise by 90 degrees within thehorizontal plane and the Z axis taken in the vertical direction, as inthe diagram. Then, the relative coordinates (Xc, Yc, Zc) of the camera24 are acquired in the real coordinate system and the positionaldeviation amount of the forks 2 is computed based on the relativecoordinates. The relative coordinates (Xc, Yc, Zc) in the realcoordinate system are computed by performing geometric conversion usingthe data I, J and D computed in the screen coordinate system shown inFIG. 6.

[0102] The following will discuss a method of obtaining the relativecoordinates (Xc, Yc, Zc) of the camera 24 in the real coordinate systemfrom the I, J and D values.

[0103]FIG. 8 shows the state in which the camera and the mark are seenfrom above in the real coordinate system. FIG. 9 shows the similarrelationship between the real coordinate system and the screencoordinate system. The left-hand side in the diagram shows the YZ planeof the real coordinate system picked up by the camera 24 and theright-hand side in the diagram shows the IJ plane of the screencoordinate system of the image picked up by the camera 24. Those twoimages are similar to each other if the distortion of the images is notconsidered.

[0104] As shown in FIGS. 8 and 9, the horizontal width of the imagepickup range in the real coordinate system is indicated by 2L·tan α,which becomes equal to the number of horizontal pixels H of the screen28A in the screen coordinate system. The angle “α” is a half thehorizontal angle of view of the camera 24, as shown in FIG. 8. L is thedistance between the camera 24 and the YZ plane and is equal to|Xc|(L=|Xc|). A center distance d of the two patterns P, P in the mark Min the real coordinate system is expressed by the center distance D inthe screen coordinate system. That is, the similarity ratio of the realcoordinate system to the screen coordinate system becomes d:D. Withregard to the horizontal coordinates from the origin O to the center ofthe image, Yc in the real coordinate system correspond to I−H/2 in thescreen coordinate system. Further, with regard to the verticalcoordinates from the origin O to the center of the image, Zc in the realcoordinate system corresponds to J−V/2 in the screen coordinate system.

[0105] The relative coordinates (Xc, Yc, Zc) of the camera 24 in thereal coordinate system (XYZ coordinate system) shown in FIG. 7 arecomputed from the following equations by performing geometric conversionbased on the similar relationship in FIG. 9 by using the coordinates (I,J) in the screen coordinate system and the value of the distance D.

Xc=−L=−Hd/(2D tan α)  (1)

Yc=d/D(I−H/2)  (2)

Zc=d/D(J−V/2)  (3)

[0106] As H, V, α and d values are known values, the coordinates (Xc,Yc, Zc) are acquired if the I, J and D values are computed.

[0107] The load handling control section 47 has a relative coordinatecomputing section 85 and a control amount computing section 86. Therelative coordinate computing section 85 calculates relative coordinatesOC (Xc, Yc, Zc) of the camera 24 in the real coordinate system based onthe data I, J and D sent to the load handling control section 47 fromthe image control section 46. The control amount computing section 86calculates a positional deviation amount between the forks 2 and thetarget position at the time of positioning the forks 2 to the loadhandling target, based on the relative coordinates (Xc, Yc, Zc) of thecamera 24 obtained in the real coordinate system. That is, the movingdistances in the X, Y, and Z directions needed to position the forks 2to the load handling target are calculated.

[0108]FIG. 11 is for explaining the flow of the control process from theimage recognition process to the automatic fork positioning control.

[0109] To begin with, when image data is acquired, the image recognitionprocessing section 81 reads the template T from the template memorysection 82 and performs a pattern matching process. The image computingsection 83 calculates the barycentric coordinates (I, J) of the mark Mand the pattern center distance D in the screen coordinate system (pixellevel) based on the position of the pattern recognized by the imagerecognition processing section 81.

[0110] The data I, J and D calculated here are sent to the displayposition determining section 84. At the time the forks 2 are positionedto the load handling target (the pallet 41 or the shelf plate 42), thedisplay position determining section 84 calculates the coordinates ofthe moving target point of the mark M on the screen 28A (screencoordinate system) based on the data I, J and D.

[0111] As shown in FIG. 10, a camera position C, a fork position F, apallet position P and a mark barycentric position (origin) O are set.Then, in consideration of a vector FP when the fork position F ispositioned to the pallet position P at the time of a load pickup work,there is a relationship of vector FP=vector OP−vector OC−vector CF.Assume that the point C and point F are on a common vertical line andthe point O and point P are positioned on another common vertical line.The vector CF is equivalent to the distance between the camera positionC and the fork position F, and the vector OP is equivalent to thedistance between the mark barycentric position O and the pallet positionP and both are known information.

[0112] Given that for those known information, the components of thevector OP are (Xp, Yp, Zp) and the components of the vector CF are (Xcf,Ycf, Zcf), the coordinates (It, Jt) of the moving target point to whichthe mark M1 should be moved on the screen 28A to position the forks 2 tothe pallet 41 are given by the following equations.

It=H/2+(Yp−Ycf)*D/d  (4)

Jt=V/2+(Zp−Zcf)*D/d  (5)

[0113] where Yp, Zp, Ycf and Zcf are known values.

[0114] Similarly, let us consider the case of a load deposition work. Incase where the forks 2 are positioned to the shelf plate 42, a loaddeposition position R is the position apart upward from a shelf surface42A by a predetermined distance (10 to 20 cm). In this case, the vectorsCF and OR are known information. The vector OR is equivalent to thedistance between the mark barycentric position O and the load depositionposition R. Given that for the known information, the components of thevector OR are (Xr, Yr, Zr) and the components of the vector CF are (Xcf,Ycf, Zcf), the coordinates (It, Jt) of the moving target point to whichthe mark M2 should be moved on the screen 28A to position the forks 2 tothe load deposition position R are given by the following equations.

It=H/2+(Yr−Ycf)*D/d  (6)

Jt=V/2+(Zr−Zcf)*D/d  (7)

[0115] where Yr, Zr, Ycf and Zcf are known values.

[0116] How to acquire the individual equations (4) to (7) will bediscussed later.

[0117] The coordinates (It, Jt) of the moving target point that has beencomputed by the display position determining section 84 are sent to thedrawing display section 77 and a drawing process to draw a moving targetpoint mark 87 shown in FIG. 13 in the position of the moving targetpoint on the image on the screen 28A is performed. The moving targetpoint mark 87 is comprised of a figure having four triangles arranged atequal angular intervals, and the portion that is surrounded by fourclose vertexes indicates the moving target point.

[0118] The data I, J and D are sent to the load handling control section47. The relative coordinate computing section 85 calculates the relativecoordinates OC (Xc, Yc, Zc) of the camera 24 in the real coordinatesystem based on the data I, J and D. The control amount computingsection 86 calculates a positional deviation amount (individualcomponents of the vector FP) between the forks 2 and the target positionat the time of positioning the forks 2 to the load handling target byusing the known information (vectors CF, OP) based on the relativecoordinates (Xc, Yc, Zc) of the camera 24. That is, the moving distancesin the X, Y and Z directions needed to position the forks 2 to the loadhandling target are calculated.

[0119] The vector FP is expressed by the following equation.

Vector FP=−vector CF−vector OC+vector OP

[0120] Thus, the positional deviation amount (Xfp, Yfp, Zfp) at the timeof a load deposition work becomes

(Xfp, Yfp, Zfp)=(Xcf−Xc+Xp, Ycf−Yc+Yp, Zcf−Zc+Zp)

[0121] and the positional deviation amount (Xfr, Yfr, Zfr) at the timeof the load deposition work becomes

(Xfr, Yfr, Zfr)=(Xcf−Xc+Xr, Ycf−Yc+Yr, Zcf−Zc+Zr).

[0122] Data of those positional deviation amounts are sent to the imagecontrol section 46. The drawing display section 77 reads numerical dataof the distances in the X, Y and Z directions equivalent to thepositional deviation amount data from the drawing data memory section 78and displays the data on a character information display area at theupper portion of the screen 28A, as shown in FIG. 13. As a result, thedistances in the X, Y and Z directions of the forks 2 needed to positionthe forks 2 to the load handling target are displayed. On the screens inFIG. 13(a) and (b), “distance” indicates the moving distance of theforks to the load handling target, “latitude” indicates the movingdistance of the forks in the left and right direction (the rightwarddirection is positive) and “height” indicates the moving distance of theforks in the up and down direction (upward direction is positive).

[0123] For example, positioning information of “distance Xfp”, “latitudeYfp” and “height Zfp” are displayed in characters on the screen 28A atthe time of a load pickup work and positioning information of “distanceXfr”, “latitude Yfr” and “height Zfr” are displayed in characters on thescreen 28A at the time of a load deposition work. It is therefore easyto see in which direction and how much the forks 2 should be moved.

[0124] Then, the load handling control section 47 outputs control amountinstruction values to make the vector FP to “0” to the solenoid drivecircuit 50. In the present embodiment, automatic positioning control isperformed only in the up and down direction and left and right directionof the forks 2 and control in the forward and backward direction (reachdirection) is done by the manual operation by the driver. Therefore, theload handling control section 47 outputs values corresponding to theindividual shift amounts of the forks 2 in the up and down direction andleft and right direction to make the Y and Z components of the vector FPto “0” as control amount instruction values. Accordingly, the forks 2are automatically positioned in the up and down direction and left andright direction. As a result, the forks 2 are positioned to theinsertion holes 41A of the pallet 41 in a load pickup mode and arepositioned to the target position apart upward from the shelf plate 42by a predetermined distance in a load deposition mode. After thepositioning, a load pickup work or a load deposition work is carried outby performing a reach operation to cause the mast 13 to reach. The reachoperation of the forks 2 may be automatically controlled.

[0125] Next, a method of calculating a moving target point will bediscussed by using FIGS. 12(a) and (b). FIG. 12 shows the realcoordinate system and (b) in the same diagram shows the screencoordinate system.

[0126] Let us consider an imaginary plane (YZ plane) G including themark M in the real coordinate system as shown in FIG. 12(a). Thisimaginary plane G is equivalent to an image pickup area picked up by thecamera 24 and displayed on the screen 28A, and is assumed to be movedtogether with the movement of the camera 24. In consideration of a loadpickup work, to position the forks 2 to the pallet 41, the camera 24 ismoved parallel to the imaginary plane G according to the vector FP (Xcomponent not considered) and the imaginary plane G is moved togetherwith the camera 24, so that the mark M on the imaginary plane G is movedtoward the moving target point mark 87 and the origin O coincides withthe moving target point T. Thus,

vector OT=−vector FP  (8)

[0127] is given.

[0128] Let the screen coordinate system of the moving target point T be(It, Jt) as shown in FIG. 12(b). The components (Xc, Yc, Zc) of thevector OC directed toward the camera position C from the origin O(screen coordinates (I, J)) in the real coordinate system are expressedby the equations (2) and (3) by using the screen coordinates (I, J).With regard to the components (Xtc, Ytc, Ztc) of the vector TC directedtoward the camera position C from the moving target point T (screencoordinates (I, J)), therefore, the relationships in the equations (2)and (3) are likewise met by using the screen coordinates (I, J), so thatthey are expressed as follows.

Ytc=d/D(It−H/2)  (9)

Ztc=d/D(Jt−V/2)  (10)

[0129] From the relationship of

vector TC=vector OC−vector OT  (11),

[0130] substituting the relationship in the equation (8) into theequation (11) yields an equation (12).

vector TC=vector OC+vector FP  (12)

[0131] Substituting the relationship in the following equation (13) intothe equation (12) yields an equation (14).

vector FP=vector OP−vector CF−vector OC  (13)

vector TC=vector OP−vector CF  (14)

[0132] The components of the vector OP are (Xp, Yp, Zp) and thecomponents of the vector CF are (Xcf, Ycf, Zcf). To obtain thecoordinates (It, Jt) of the moving target point, assuming that the markM is replaced with the moving target point T, the computation has onlyto be carried out by replacing the components of the vector OC with thecomponents of the vector TC and replacing I with It and J with Jt in theequations (2) and (3).

[0133] The components (Xtc, Ytc, Ztc) of the vector TC are expressed byan equation (15) by using the relationship in the equation (14).

(Xtc, Ytc, Ztc)=(Xp, Yp, Zp)−(Xcf, Ycf, Zcf)=(Xp Xcf, Yp−Ycf,Zp−Zcf)  (15)

[0134] Thus, the relationship in an equation (16) is obtained from theequations (9) and (15).

Yp−Ycf=d/D(It−H/2)  (16)

[0135] Further, the relationship in an equation (17) is obtained fromthe equations (10) and (15).

Zp−Zcf=d/D(Jt−V/2)  (17)

[0136] Solving the equations (16) and (17) for It and Jt respectively,the coordinates (It, Jt) of the moving target point T at the time of aload pickup work are acquired as in the equations (4) and (5).

[0137] Likewise, let us consider a load deposition work. To position theforks 2 to the load deposition position R lying above the shelf plate 42by a predetermined distance (10 to 20 cm), the camera 24 is movedparallel to the imaginary plane G according to the vector FR (Xcomponent not considered) and the imaginary plane G is moved togetherwith the camera 24, so that the mark M2 on the imaginary plane G ismoved toward the moving target point mark 87 and the origin O coincideswith the moving target point T. Thus,

vector OT=−vector FR  (18)

[0138] is given. Substituting the equation (18) into the equation (11)yields the following equation (19).

vector TC=vector OC+vector FR  (19) _

[0139] Substituting the relationship in the following equation (20) intothe equation (19) yields an equation (21).

vector FR=vector OR−vector CF−vector OC  (20)

vector TC=vector OR−vector CF  (21)

[0140] The components of the vector OR are (Xr, Yr, Zr) and thecomponents of the vector CF are (Xcf, Ycf, Zcf). To obtain thecoordinates (It, Jt) of the moving target point, assuming that the markM is replaced with the moving target point T, the computation has onlyto be carried out by replacing the components of the vector OC with thecomponents of the vector TC and replacing I with It and J with Jt in theequations (2) and (3).

[0141] The components (Xtc, Ytc, Ztc) of the vector TC are expressed byan equation (22) by using the relationship in the equation (21).

(Xtc, Ytc, Ztc)=(Xr, Yr, Zr)−(Xcf, Ycf, Zcf)=(Xr−Xcf, Yr−Yef,Zr−Zcf)  (22)

[0142] Because information to be obtained finally is the screencoordinates when the mark M is on the final reaching point, as therelationship in the equation (22) is substituted into the equations (2)and (3) and they are solved for the coordinates (It, Jt) of the movingtarget point, the coordinates of the moving target point in a loaddeposition work are obtained as the equations (6) and (7).

[0143] A description will now be given of the automatic fork positioningcontrol and the process of drawing the moving target point mark 87.

[0144] First, when the forks 2 are lifted at a height exceeding the setheight, a process for image recognition of the mark M is carried outbased on image data picked up by the camera 24. That is, imageprocessing to identify the mark M1 is carried out using the template T1in a load pickup mode and image processing to identify the mark M2 iscarried out using the template T2 in a load deposition mode. Then,positional data I, J and D values of the image-recognized mark M on thescreen are obtained.

[0145] The display position determining section 84 computes thecoordinates (It, Jt) of the moving target point T using the data D valueamong them. That is, the coordinates (It, Jt) of the moving target pointare computed according to the equations (4) and (5) at the time of aload pickup work and the coordinates (It, Jt) of the moving target pointare computed according to the equations (6) and (7) at the time of aload deposition work. Those coordinate data (It, Jt) are sent to thedrawing display section 77. The drawing display section 77 reads figuredata for a display mark from the drawing data memory section 78according to an instruction from the display position determiningsection 84 and displays the moving target point mark 87 at thecoordinates (It, Jt) as shown in FIG. 13(a) in such a way as to overliethe image.

[0146] On the screen 28A at the time of a load pickup work, the movingtarget point mark 87 indicating the moving target point T where the markM1 should reach finally at the time the forks 2 are positioned to thepallet 41 is displayed. On the screen 28A at the time of a loaddeposition work, on the other hand, the moving target point mark 87indicating the moving target point T where the mark M2 should reachfinally at the time the forks 2 are positioned above the shelf plate 42by a predetermined distance is displayed.

[0147] As the activation switch 38 of the multi lever 31 is operated,automatic fork positioning control is initiated. The load handlingcontrol section 47 computes the relative positional coordinates (Xc, Yc,Zc) of the camera 24 with the mark M as the origin O based on thepositional data I, J and D values. Then, to set the vector FP to zero,control amounts for setting both Yc and Zc values to zero is obtained.Then, the load handling control section 47 performs current valuecontrol of the electromagnetic proportional valves 65 and 66 for liftingand the electromagnetic proportional valve 68 for side shifting via thesolenoid drive circuit 44 based on the control amounts and performsdrive control of the lift cylinders 15A and 15B and the side shiftcylinder 71, thereby positioning the forks 2. As a result, the forks 2are moved in the up and down direction by Zc and moved in the left andright direction by −Yc.

[0148] As the forks 2 are moved, at the time of a load pickup work, forexample, the center point of the mark M1 matches with the moving targetpoint T or the center point of the moving target point mark 87 and theforks 2 are positioned to the load pickup position that matches with theinsertion holes 41A, as shown in FIG. 13(b). At the time of a loaddeposition work, on the other hand, the center point of the mark M2matches with the moving target point T and the forks 2 are positioned tothe load deposition position that lies above the shelf surface 42A byabout 10 to 20 cm.

[0149] As the moving target point T to which the mark M should be movedcan be seen on the screen 28A this way, it is possible to easilyvisually check if the forks 2 are positioned by confirming thecoincidence of the center points of the mark M and the moving targetpoint mark 87 with each other. At the time of a load carrying work, thedriver can also determine whether or not the forks 2 are positionedcorrectly to an intended load handling target.

[0150] The embodiment has the following advantages.

[0151] (1) At the time automatic fork positioning control is executed,the moving target point mark 87 indicating the moving target point ofthe mark M affixed to a load handling target is drawn on an image on thescreen 28A. Therefore, the moving target point to which the mark Mshould be moved at the time of positioning the forks 2 to the loadhandling target can be visually checked at a glance through the screen28A from the drawn position of the moving target point mark 87 on thescreen 28A. It is therefore possible to check how the forks 2 arepositioned from the process in which the mark M affixed to the loadhandling target is moved on the screen 28A toward the moving targetpoint mark 87. Then, the completion of the automatic positioning controlof the forks 2 can be known through the screen 28A when both marks M and87 coincide with each other on the screen 28A.

[0152] (2) As the method of selecting the mark M for position detection(subject to be image-recognized) affixed to a load handling target anddrawing the mark 87 on the moving target point is employed, by payingattention to the two marks M and 87 displayed or drawn on the screen28A, the state of positioning the forks 2 can easily be grasped fromtheir positional relationship.

[0153] (3) By checking if the mark M matched with the moving targetpoint mark 87 is on the pallet 41 or on the shelf plate 42, it ispossible to easily find out through the image on the screen 28A whetherthe positioning of the forks 2 has been successful or failed.

[0154] (4) As the deviation amounts between the forks 2 and the loadhandling target 41, 42 in the three directions (X, Y and Z directions)are displayed in numerical values on the screen 28A, the driver can seein which direction and how much distance the forks 2 should be moved.

[0155] (5) In the automatic fork positioning control, the driver can seethe progressing state of the control and can obtain a sense of securityin the satisfactory progress of the control and a timely preparation forthe next operation at the time of the control is finished.

[0156] (6) As the moving target point mark 87 is drawn distinguishablybetween the load pickup mode and load deposition mode, it is possible tocope with both load handling modes.

[0157] (7) As the lifting system for lifting the camera 24 up and downwith respect to the carriage 14, the camera 24 is moved and placed intwo positions, the storage position and the lift-down position, inaccordance with the type of the load carrying work (load pickup work,load deposition work). As a result, the image of the work area can bepicked up by the camera 24 placed in the storage position atapproximately the same height as the forks 2 at the time of a loadpickup work in which there is no load on the forks 2. At the time of aload deposition work in which there is a load on the forks 2, on theother hand, the image of the work area can be picked up by the camera 24placed in the lift-down position without being obstructed by the load.Therefore, the image pickup angle for an image displayed on the screen28A is convenient for the positioning of the forks 2.

[0158] (8) By using the camera 24 and display device 28 provided toassist a load carrying work at a high place, the moving target pointmark 87, which becomes a mark for visual confirmation of the movingtarget point is drawn on the screen 28A of the display device 28. Thatis, the position of the mark M is calculated through an imagerecognition process using image data picked up by camera 24 and thecoordinates of the moving target point are calculated by using thepositional data (I, J, D) of the mark M, acquired for automatic forkpositioning control, to thereby obtain the drawing position of themoving target point mark 87.

[0159] Therefore, fewer calculation processes, which are added only forthe positional calculation of the moving target point, are required andthe load of the CPU for automatic fork positioning control need not beincreased much even if a drawing process of drawing the moving targetpoint mark 87 on the screen 28A is added.

[0160] Second Embodiment

[0161] In the second embodiment, a load handling operation aidingapparatus of a type that has a camera fixed to the mast is adopted.

[0162] As shown in FIG. 14, the mast 13 comprises the outer mast 13A,the middle mast 13B and the inner mast 13C in order from the outer side.A beam 194 is laid horizontally in a position slightly above the heightdirectional center of the inner mast 13C and a camera 195 is fixed tothe bottom surface of the beam 194. An image pickup section 195A of thecamera 195 faces forward to be able to pick up the image of a work areaof the forks 2.

[0163]FIG. 15 shows a part of a load handling apparatus (mast assembly)from the front and shows the carriage 14 placed in the topmost positionof the inner mast 13C. In that state, the camera 195 is positioned belowthe forks 2 by a predetermined distance and is positioned in a middle ofa pair of forks 2 with the carriage 14 not side-shifted with regard tothe left and right direction (vehicle's widthwise direction). The mast13 is of a telescopic type (full free type) and does not startprotracting until the carriage 14 reaches the topmost position of theinner mast 13C. When the mast protracts after the carriage 14 reachesthe topmost position of the inner mast 13C, i.e., at a height equal toor higher than a predetermined height after the carriage 14 reaches thetopmost position of the inner mast 13C, therefore, the positionalrelationship between the forks 2 and the camera 195 is always keptconstant in the up and down direction.

[0164] The position of the camera 195 shown in FIG. 15 is approximatelyequivalent to the position at which the camera is moved down withrespect to the forks 2 in the first embodiment. Even at the time of aload deposition work in which a load is placed on the forks 2, the markM2 affixed to the shelf plate 42 as a load handling target at that timecan be picked up by the camera 195. Of course, at the time of a loadpickup work in which no load is placed on the forks 2, the mark M1affixed to the pallet 41 as a load handling target at that time can bepicked up. As apparent from the above, the embodiment differs from thefirst embodiment only in that the camera 95 is secured to the inner mast13C, and the controller 45 electrically connected to the camera 195performs image processing and load handling control using image datapicked up by the camera 195 as per the first embodiment.

[0165] A stroke sensor 73 is provided on the side shift cylinder 71 anddetects the stroke amount of the side shift cylinder 71. The sideshifting amount of the forks 2 is grasped from the detection result fromthe stroke sensor 73 and the relative positional relationship betweenthe forks 2 and the camera 195 in the left and right direction (Ydirection) or the deviation amount between the camera 195 and the forks2 in the Y direction is grasped.

[0166]FIG. 16 shows the control circuit of the load handling operationaiding apparatus 20. As shown in the diagram, the aiding apparatus 20basically has the same electrical structure as that of the firstembodiment. As the camera 195 is fixed to the inner mast 13C, however,sensors for the camera lifting apparatus and the actuator becomeunnecessary and are thus omitted. In the present embodiment, thedeviation amount between the camera 195 and the forks 2 in the Ydirection is acquired from the measured value from the stroke sensor 73,and using it, the moving target point and the deviation amounts betweenthe forks 2 and the load handling target in the X, Y and Z directionsare computed.

[0167] A description will now be given of a method of calculating themoving target point in the present embodiment.

[0168] To position the forks 2 to the pallet 41 at the time of a loadpickup work, the coordinates (It, Jt) of the moving target point towhich the mark M1 should be moved on the screen 28A are given by thefollowing equations as per the first embodiment.

It=H/2+(Yp−Ycf)*D/d  (4)

Jt=V/2+(Zp−Zcf)*D/d  (5)

[0169] where It is the horizontal coordinate of the moving target pointon the screen, Jt is the vertical coordinate of the moving target pointon the screen, H is the number of horizontal pixels of the screen, V isthe number of vertical pixels of the screen, Yp is the horizontalcoordinate of the moving target point of the center position of forks asseen from the mark M1, Zp is the vertical coordinate of the movingtarget point of the center position of forks as seen from the mark M1,Ycf is the horizontal coordinate of the center position of the forks asseen from the camera, Zcf is the vertical coordinate of the centerposition of the forks as seen from the camera, d is the actual distanceof the mark, and D is a mark size [pixels] acquired through imageprocessing. Ycf is measured and calculated by using the stroke sensor73. Yp, Zp and Zcf are known values. The center position of a pair offorks is the position at which a bisector of the layout interval of theforks intersects a line passing through the bent portions of the forks.

[0170] At the time of a load deposition work, the coordinates (It, Jt)of the moving target point to which the mark M2 should be moved on thescreen 28A to position the forks 2 to the load deposition position Rlying above the shelf surface 42A by a predetermined distance (10 to 20cm) with respect to the shelf plate 42 are given by the followingequations.

It=H/2+(Yr−Ycf)*D/d  (6)

Jt=V/2+(Zr−Zcf)*D/d  (7)

[0171] where Yr is the horizontal coordinate of the moving target pointat the horizontal center of the bases of the forks as seen from the markM2, and Zr is the vertical coordinate of the moving target point at thehorizontal center of the bases of the forks as seen from the mark M2,and both are known values.

[0172] Although Ycf is a fixed value for the camera 24 is attached tothe side shifter 16 and moved together with the forks 2 in the firstembodiment, Ycf is a variable which varies according to the state ofside shifting in this embodiment since the camera 24 does not move evenwhen the forks 2 are moved sideways by side shifting. Therefore, Ycfused in the equations (4) and (6) is obtained by measurement with thestroke sensor 73.

[0173] As the amount of retraction ΔY from the fully protracted state ofthe side shift cylinder 71 is measured by the stroke sensor 73 and letYcf when ΔY=0 be Ycf0, the variable Ycf is expressed by the followingequation.

Ycf=Ycf0+ΔY  (23)

[0174] Substituting the equation (23) into the equations (4) and (6)yields the following equations.

It=H/2+(Yp−Ycf0−ΔY)*D/d  (24)

It=H/2+(Yr−Ycf0−ΔY)*D/d  (25)

[0175] where Ycf0 is the horizontal coordinate of the horizontal centerof the bases of the forks at the time the side shift cylinder 71 isfully protracted, as seen from the camera 24, ΔY is the retracted amount(measured by the stroke sensor 73) from the fully protracted state ofthe side shift cylinder 71, and Zcf is the vertical coordinate of thehorizontal center of the bases of the forks as seen from the camera.

[0176] The second embodiment has the following advantages.

[0177] As the camera is fixed to the inner mast 13C, it is possible toeliminate the need for the camera lifting apparatus used in the firstembodiment so that the image pickup system can be realized with a simplestructure and at a low cost. What is more, as the moving target pointmark 87 is drawn on the screen 28A, the driver can visually check, at aglance, the moving target point to which the forks 2 should be moved,from the mark 87 drawn on the image on the screen 28A. Therefore, theadvantages (1) to (6) and (8) discussed in the first embodiment are alsoobtained.

[0178] Third Embodiment

[0179] The third embodiment differs from the individual embodiments inthat automatic control to automatically position the forks is notemployed. FIG. 17 shows the control circuit of a load handling operationaiding apparatus. The camera 195 is fixed to the inner mast 13C as perthe second embodiment.

[0180] Because automatic positioning control is not carried out, therelative coordinate computing section 85 and the control amountcomputing section 86 in the load handling control section 47 areomitted. The load handling control section 47 is electrically connectedwith individual sensors 101 to 104 for detecting the operations of loadhandling levers provided on the instrument panel in the driver's seat 9,namely, a lift lever 96, a reach lever 97, a side shift lever 98 and atilt lever 99, and sensors similar to the sensors 58 to 60 and 73 of thesecond embodiment. The load handling control section 47 performs currentvalue control of the solenoids of the electromagnetic proportionalvalves 65 to 69 via the solenoid drive circuit 50 based on signals fromthe individual sensors 101 to 104, and performs drive control of thecylinders 12, 15A, 15B, 71 and 72 in accordance with the operations ofthe individual levers 96 to 99. The lift lever 96 and the side shiftlever 98 constitute manual operation means.

[0181] Although the forklift according to the present embodiment is of amanual operation type, which drives and controls the cylinders by manualoperation of the levers, the image of a work area at a high place pickedup by the camera 195 is displayed on the screen 28A of the displaydevice 28. The image control section 46 has a structure similar to thatof each of the above-described embodiments, and performs mark imagerecognition process, mark positional data calculating process, acalculating process for a moving target point and a drawing process forpositioning information, such as a moving target point mark, based onimage data picked up by the camera 195.

[0182] At a height equal to or higher than a predetermined height,therefore, the moving target point mark 87 indicating the moving targetpoint of the forks 2 is drawn on the screen 28A. Therefore, the image ofa work area at a high place is displayed on the screen 28A and themoving target point can be visually checked from the mark 87 when thepositioning of the forks 2 is manually done while viewing the screen28A. The deviation amounts between the forks 2 and the load handlingtarget 41, 42 in the X, Y and Z directions are also drawn on the screen28A. Therefore, the advantages (2) and (4) to (6) can be obtained as pereach of the above-described embodiments.

[0183] According to the present embodiment, the driver can reliablyposition the forks 2 to the load handling target 41, 42 by performingthe load handling operation in such a way that the deviation amountsbetween the forks 2 and the load handling target 41, 42 in the threedirections, drawn on the screen 28A, become “0”. This can improve theefficiency of a load carrying work in a position that is difficult tosee with eyes, such as a highly lifted place.

[0184] The embodiment is not limited to what is described above but canbe worked in the following modes.

[0185] In each of the above-described embodiments, whether the contentof the load carrying work is a load pickup work or a load depositionwork is discriminated based on the detected value from the load weightsensor, according to the type of the discriminated load carrying work,and the target mark M is determined to decide whether the load handlingtarget is a pallet or a shelf plate. Instead, a method of providing abutton to be operated to designate a load carrying work on, for example,the instrument panel in the driver's seat and designating the type ofthe load carrying work to the controller by a driver's operating thebutton can be employed.

[0186] The target for an image recognition process(to-be-subjected-to-image-recognition target) based on image data pickedup by the camera is not limited to the mark M1, M2 affixed to the loadhandling target. For example, a scheme of performing an imagerecognition process with the shape or the like of the pallet 41 or theshelf plate 42 as a pattern and calculating the position of the loadhandling target can be employed, too.

[0187] The design of the moving target point mark 87 is not limited tothose of the above-described embodiments. Any shape that can specify amoving target point is sufficient. For example, a figure whose shape hasdirectivity, such as an arrow figure indicating a moving target pointcan be used. A mark with a predetermined shape, such as a circle,triangle, rectangle and polygon, may be drawn in such a way that thebarycenter coincides with the moving target point. A mark to bedisplayed on the screen as a mark indicating a target moving point cantake any design or figure. For example, it may be a “cross”, “point”,“line” or the like. If it is cross lines, for example, positioning hasonly to be done in such a way that the barycenter of the mark Mcoincides with two vertical and horizontal lines constituting the crosslines, so that an operation to position the forks is easy in case of themanual operation type. Further, it may be a radial figure, other linefigures and illustrations. A figure which has a point symmetricalproperty as used in each of the above-described embodiments is howeverpreferable because it is easy to specify a point. A mark (target pointsign) is not limited to a still picture but may be a moving picture. Themark may be flickered or its color may be changed with the passage oftime. Because the positional range where the forks can be inserted intothe holes of a pallet can be regarded as a positioning range, thedisplay color of the sign may be changed, when the forks are positionedwithin this positioning range, to visually notify a driver to thateffect.

[0188] If a driver can be visually notified of the moving target point,it should not necessarily be limited to displaying a mark in theposition of the moving target point. For example, a scheme of drawingtwo signs separately indicating the I coordinate and J coordinate of themoving target point along two vertical and horizontal sides of thescreen 28A and specifying the moving target point on the screen byspecifying the I coordinate and J coordinate from both signs can beemployed.

[0189] Although a radial figure is used as an image recognition mark, itis not limited to such a figure. It may be a simple figure, such as arectangle (

) or a triangle (Δ). While it is necessary to prepare multiple templatesdepending on the pattern matching, which takes time in an imagerecognition process, the position of a load handling target can bedetected. An image recognition method other than pattern matching may beused to detect the position of a load handling target. It is possible toemploy a method of acquiring the coordinates of a moving target pointusing a method other than image recognition. For example, a method ofdetecting the position of a load handling target by detecting ato-be-detected portion affixed to a load handling target, such as apallet or a shelf portion (shelf plate), can be employed.

[0190] As positioning information, information is sufficient which showsthe direction and the deviation amount at the time of positioning a loadcarrying apparatus to a load handling target. That is, unlike in theabove-mentioned embodiment, it need not be the distance itself to whichthe forks 2 are to be shifted for positioning. For example, a gaugeindicating the shift amount for positioning in the YZ directions as arelative amount with the screen scale being 100 may be drawn.

[0191] Although the moving target point mark 87 in each of theabove-described embodiments is the moving target point of the mark M onthe screen 28A, it should not necessarily be the moving target point ofthe mark M. For example, with a hole 41A in one side of the pallet 41(e.g., the right-hand side) taken as a reference, a moving target pointmark indicating the moving target point of the hole 41A may be drawn. Inshort, it is sufficient to set a reference point convenient at the timeof positioning a load carrying apparatus to a load handling targetsomewhere and draw a sign indicating a moving target point to which thereference point should be moved at the time of positioning the loadcarrying apparatus to the load handling target. The reference point maybe set anywhere outside the vehicle as long as it performs the role, andit can be a part of the load handling target, a specific location aroundthe load handling target (e.g., a specific location of a rack), or amark affixed to the part or the locations. In case where the referencepoint is a mark, a mark for image recognition should not necessarily beused as the mark but a mark for the reference point can be providedseparate from the mark M1, M2.

[0192] Although the forks 2 can be positioned in the up and downdirection and left and right direction with the moving target point markin each of the above-described embodiments, a moving target point markwhich can position only in one direction in up and down or left andright may be displayed on the screen.

[0193] In case of manual operation to position the forks as in the thirdembodiment, it is necessary to manipulate the forks in the up and downdirection and left and right direction. At this time, a method ofindicating positions, if matched in the moving direction in each of theup and down direction and left and right direction, in a display modevisually indicating to that effect or notifying it by sounds isemployed.

[0194] In the third embodiment, the camera 24 may be provided on theinner mast 13C in a liftable manner. That is, the camera 24 is attachedto the beam of the inner mast 13A in a liftable manner between twopositions equivalent to the storage position and lift-down position inthe first embodiment in the relative positional relationship between thecamera 24 and the forks 2. An image is picked up by the camera 24 placedin the storage position at the time of a load pickup work and is pickedup by the camera 24 placed in the lift-down position at the time of aload deposition work.

[0195] The detection means that acquires positional information of aload handling target is not limited to image processing of image datapicked up by the camera. For example, a method of measuring the positionof a load handling target from a detected value from an ultrasonicsensor, proximity sensor, a laser sensor or the like in use andcalculating the deviation amount or the moving target point can be used.In this case, a mark as a to-be-detected target is affixed to a loadhandling target and the moving target point of the mark can be used as adrawing position of the moving target point mark. In case of employing asensor-based position detection method other than image processing, thecamera may be used together or may be eliminated. In case of eliminatingthe camera, for example, it is possible to display numerical values inthe XYZ directions on the screen of the display device or draw only amark showing the positional relationship between the load handlingtarget and the moving target point. Even in case where there is acamera, a picked-up image may be used only in position detection, andlikewise, only numerical values or only a mark may be drawn on thescreen.

[0196] In each of the above-described embodiments, the mark M affixed toa load handling target is matched with the moving target point mark 87on the screen as a method of supporting fork positioning. By way ofcontrast, it is possible to employ a method of drawing a mark indicatingthe current fork position, in place of a picked-up mark, on the screenin the proper position and drawing another mark at the moving targetpoint corresponding to that mark to thereby support fork positioningfrom the positional relationship between the two drawn marks.

[0197] Although the deviation amounts (moving distances) in the threedirections (XYZ directions) are displayed in each of the above-describedembodiments, only the YZ directions or the Z direction may be displayed.

[0198] It is not limited to an industrial vehicle in which forks areprovided movable in the vehicle's widthwise direction. For example, itmay be adapted to a forklift that does not have a side shift function.

[0199] The load carrying apparatus is not limited to forks. It may be anattachment other than the forks. It may be a clamping apparatus, whichfirmly holds a load or a bucket for scooping a load. Further, it may bea load carrying apparatus, which holds a load with magnetic force.

[0200] The industrial vehicle is not limited to reach type forklift. Itmay be a counter balance type forklift. Further, the industrial vehicleis not limited to a forklift. For example, it may be a power shovel. Aload to be a target for a load carrying work is not limited to a palletor a load that is handled on a pallet, but may be a log, a roll ofpaper, a container, or a fluid or the like, such as sediment, which ishandled in a work by industrial vehicles. The load includes a member onwhich a load is deposited and a load container box other than thepallet.

[0201] Fourth Embodiment

[0202] The fourth embodiment of the present invention will be describedmainly on those that differ from the above-described embodimentsaccording to FIGS. 18 to 21. In this embodiment, a load carryingapparatus performs a predetermined operation in accordance with the typeof a load carrying work. To simplify the description, same referencesymbols are given to those constituents that are the same as those ofeach of the above-described embodiments and their detailed descriptionswill be omitted.

[0203]FIG. 18 shows marks and templates. FIG. 18(a) shows the mark M1for pallet position detection and FIG. 18(c) shows the mark M2 for rackposition detection. FIG. 18(b) shows the template T1 for the mark M1,and FIG. 18(d) shows the template T2 for the mark M2. The designs of themarks M1 and M2 in this embodiment are the same as those of theembodiment in FIG. 5 except that their white and black are inverted tothose of the designs of the marks in the embodiment in FIG. 5.

[0204] The height sensor 58 shown in FIG. 4 detects if the forks 2 areat or higher than a set height (height), and is comprised of a switchwhose ON/OFF is switched at, for example, the set height. The automaticfork positioning control is executed only when the detected height ofthe height sensor 58 is equal to or greater than the set height. Theheight sensor 58 may be a sensor capable of continuously detecting theheight of the forks 2. For example, a reel type height sensor whichdetects the amount of rotation of a reel from and on which a wire is fedout and wound in accordance with the elevation of the carriage 14 and anultrasonic height sensor which detects the stroke of a cylinder from themeasured time by which an ultrasonic wave that propagates in a fluid inthe lift cylinders 15 is reflected at a piston and returned can beemployed as the height sensor 58.

[0205] The load weight sensor 59 detects the weight of the load 43placed on the forks 2, and is comprised of a pressure sensor whichdetects the hydraulic pressure in the lift cylinder 15B in the presentembodiment. The load weight sensor 59 sends out a signal of a voltagevalue according to the weight of the load 43 on the forks 2.

[0206] The load handling control section 47 determines “a load present”when a detected value W of the load weight sensor 59 exceeds apredetermined threshold value Wo and determines “no load” when thedetected value W is equal to or smaller than the threshold value Wo. Asthe detected value W of the load weight sensor 59 includes the weightcomponent of the carriage 14 or the like, a detected value at the timeof an empty load or a value added with a small value to that detectedvalue is set as the threshold value Wo. For example, it is desirable toset the threshold value Wo in such a way that “load present” is judgedwhen only the pallet 41 is loaded.

[0207] The load handling control section 47 enters a standby mode forthe activation of the automatic positioning control of the forks onlywhen it is determined that a height condition (height H≧2 (m)) in whichthe height of the forks 2 which is grasped from the detected value ofthe height sensor 58 is equal to or greater than the set height (e.g.,about 2 meters) is satisfied. After entering the activation standbymode, the load handling control section 47 determines whether or notthere is a load 43 placed on the forks 2 based on the detected valuefrom the load weight sensor 59. When having judged that it is “no load”,the load handling control section 47 determines that a load carryingwork to be done thereafter is a load pickup work and sets the “loadpickup mode”, and when having judged that it is “load present”, itdetermines that a load carrying work to be done thereafter is a loaddeposition work and sets the “load deposition mode”. The setting processof the load handling mode is performed every predetermined time (e.g.several tens milliseconds)

[0208] The camera unit 23 is placed in the storage position when theheight H of the forks 2 is less than 2 m. When it is the “load pickupmode” during the activation standby mode (height H≧2 m), the loadhandling control section 47 places the camera unit 23 in the storageposition, whereas in the “load deposition mode”, it places the cameraunit 23 in the lift-down position. The driving of the electric actuator61 that has been activated to move the camera unit 23 is stopped whenthe camera unit 23 reaches the upper-limit position and the upper-limitposition detection switch 52 is switched on and is stopped when thecamera unit 23 reaches the lower-limit position and the lower-limitposition detection switch 53 is switched on. This causes the camera unit23 to be placed in two positions, the storage position and the lift-downposition, and the image of a load carrying work area in front of theforks is picked up by the camera 24 from those two positions.

[0209] The camera unit 23 is switched between the storage position andthe lift-down position in accordance with the “load pickup mode” and“load deposition mode”. The reason is that although it is desirable topick up an image from approximately the same height as the loaddeposition portion of the forks 2, while there is no load on the forks 2at the time of load pickup so that an image can be picked up even if thecamera 24 is positioned at approximately the same height as the forks 2,if the camera 24 is positioned at approximately the same height as theforks 2 at the time of load deposition, the load placed on the forks 2obstructs and the image of the load carrying work area cannot be pickedup. In this respect, the camera 24 is placed in the storage position atapproximately the same height as the forks 2 in “load pickup mode” whilein “load deposition mode”, the camera 24 is placed in the lift-downposition separated below the forks 2 by a predetermined distance so thatthe load does not interfere with image pickup.

[0210] The automatic fork positioning control is used in a load carryingwork at a high place where the forks 2 are positioned at a height of 2meters or higher. The driver manipulates the knob 35 of the multi lever31 to lift the forks 2 up and roughly position the forks 2 with respectto the targeting load handling target 41 (42) while viewing the screenof the display device 28. When the activation switch 38 is operated inthe state where the mark M1 (M2) affixed to the load handling target 41(42) to be a target is displayed on the screen, the automatic forkpositioning control is initiated.

[0211] The tilt angle sensor 60 detects a tilt angle with an angle atwhich the forks 2 are in a horizontal state as a reference, and iscomprised of, for example, a potentiometer. At the time the automaticfork positioning control is performed, the load handling control section47 controls driving of the tilt cylinder 72 in such a way that the forks2 are positioned horizontal based on a detected value from the tiltangle sensor 60.

[0212] When receiving a signal indicative of the manipulation of theactivation switch 38, the load handling control section 47 instructs theimage control section 46 to start the automatic positioning control ofthe forks 2 via communications. The image control section 46 receivesfrom the load handling control section 47 activation instruction data toinitiate the image recognition process and load handling mode dataindicating whether it is the load pickup mode or the load depositionmode.

[0213] The image control section 46 has a display processing section 75,an image processing section 76, a drawing display section 77, a drawingdata memory section 78 and a voice synthesizing section 79. The displayprocessing section 75 sends out a video signal input from the camera 24to the display device 28 in such a way that the image picked up by thecamera 24 is displayed on the screen. The voice synthesizing section 79performs voice synthesizing process for voice guidance or the like andoutputs a voice signal to the speaker 51. Image data from the displayprocessing section 75 is input to the image processing section 76.

[0214] The image processing section 76 performs an image recognitionprocess to compute the position of the mark M1, M2 on the screen andcomputes the positional relationship between the vehicle (forks 2) andthe load handling target based on the computed position of the mark M1,M2. The image processing section 76 has an image recognition processingsection 81, a template memory section 82, an image computing section 83and a display position determining section 84.

[0215] The image recognition processing section 81 performs an imagerecognition process based on a pattern matching process. The imagecomputing section 83 computes the positional coordinates of the mark M1(M2) in the screen coordinate system from the result of the imagerecognition process.

[0216] A start command for the image recognition process and loadhandling mode data or the like sent to the image control section 46 fromthe load handling control section 47 are input to the image processingsection 76. In the image processing section 76, upon reception of thosedata, an image recognition process is performed by the image recognitionprocessing section 81 and a control amount calculating process forautomatic fork positioning control is executed by the image computingsection 83, the relative coordinate computing section 85 and the controlamount computing section 86 by using the result of the image recognitionprocess.

[0217] First, upon reception of the start command data, the imagerecognition processing section 81 executes the image recognition processof one of the marks M1 and M2 based on the load handling mode data inputtogether then. That is, the image recognition processing section 81performs an image recognition process with the mark M1 for palletposition detection as a recognition target when the load handling moderecognized based on the load handling mode data is the load pickup modeand performs an image recognition process with the mark M2 for rackposition detection as a recognition target when it is the loaddeposition mode. Stored in the template memory section 82 are a templateT1 which is used in a pattern matching process with the mark M1 as arecognition target and a template T2 which is used in a pattern matchingprocess with the mark M2 as a recognition target (see FIG. 18 for both).At the time of executing a pattern matching process, the imageprocessing section 76 uses the template T1 when it is the load pickupmode and uses the template T2 when it is the load deposition mode. Thisimage recognition process is equivalent to a process that is executed bythe control means based on the decision result from the decision means.

[0218]FIG. 19 shows the screen coordinate system set on the screen. Inthe screen coordinate system, the coordinates are treated pixel bypixel, and in the diagram, H is the number of horizontal pixels of thescreen 28A and V is the number of vertical pixels of the screen 28A. Theimage recognition processing section 81 performs matching with respectto the two patterns P1, P1 (P2, P2) constituting the mark M1 on imagedata at two locations using the template T1 (T2) and recognizes eachpattern P1, P1, as shown in FIG. 19(b). The image computing section 83computes coordinates (I1, J1), (I2, J2) of the center points (radialcenter points) of the individual patterns P1, P1 recognized by the imagerecognition processing section 81 and acquires a barycenter (I, J) ofthe mark M1 and a center distance D between the two patterns P1, P1based on those two coordinate values.

[0219] The display position determining section 84 performs a process ofcomputing a display position (drawing position) for drawing on thescreen of the display device 28. The display position determiningsection 84 computes the drawing position for the contour of the mark andthe drawing position of a target mark to be a moving target point of themark M1 (M2) at the time of positioning the forks 2 to a load handlingtarget. When receiving drawing position data from the display positiondetermining section 84, the drawing display section 77 reads drawingdata (image data or the like) corresponding to the drawing content fromthe drawing data memory section 78 and sends a drawing signal to thedisplay processing section 75 to display the drawing content in thedesignated drawing position on the picked-up image in such a way that itis overlapped in the designated drawing position on the picked-up image.The voice synthesizing section 79 generates a voice guidance for thedriver from the speaker 51, as needed, in synchronism with the drawingtiming.

[0220] The data (I, J, D) computed by the image computing section 83 issent to the load handling control section 47 from the image controlsection 46. The load handling control section 47 has the relativecoordinate computing section 85 and the control amount computing section86. The load handling control section 47 computes control amounts (theamounts of movement in the Y and Z directions) needed to position theforks 2 to the load handling target. The calculation method is the sameas that of the above-described embodiment.

[0221] The load handling control section 47 stores the program of a loadcarrying work determining routine as shown in a flowchart in FIG. 20.This routine is executed by a CPU in the load handling control section47. The CPU executes the lifting control of the camera and automaticpositioning control of the forks in accordance with the result of thedecision in each routine. In the routine, the CPU determines whether aload carrying work to be conducted next as a result of the operation ofthe activation switch 38 is a load pickup work, or a load depositionwork, and the lifting control of the camera and automatic forkpositioning control according to the type of the load carrying work. Theautomatic fork positioning control is equivalent to automatic loadhandling control and aiding control to aid it is the camera liftingcontrol.

[0222] The following will discuss the load carrying work determiningroutine which is executed by the CPU of the load handling controlsection 47 based on FIG. 20.

[0223] First, in step (hereinafter simply written as “S”) 10, the CPUacquires the detected value from the load weight sensor 59.

[0224] In S20, it is determined whether or not the load weight W exceedsthe threshold value Wo. When the load weight W≦Wo is met, the processproceeds to S30 and when the load weight W>Wo is met, the processproceeds to S40.

[0225] In S30, it is determined that the load carrying work to becarried out next is a “load pickup work”.

[0226] In S40, it is determined that the load carrying work to becarried out next is a “load deposition work”.

[0227] The CPU always judges the contents of the load carrying work byexecuting this routine every interval of a predetermined time, andallows the forks 2 to carry out a load handling operation according tothe decision result when the height is equal to or higher than 2 m andthe activation switch 38 is operated. That is, when the height is equalto or higher than 2 m and the activation switch 38 is operated, a loadhandling operation to place the forks 2 in the “load pickup position” isperformed if the decision result is a load pickup work, while a loadhandling operation to place the forks 2 in the “load depositionposition” is performed if the decision result is a load deposition work.

[0228]FIG. 21 illustrates a load handling operation based on automaticfork positioning control, and FIG. 21(a) shows a state in which theforks are placed in a load pickup position, and FIG. 21(b) shows a statein which the forks are placed in a load deposition position. When thedetected value (load weight) from the load weight sensor 59 is equal toor smaller than the threshold value Wo (W≦Wo), as described above, it isdetermined that the load carrying work to be done next is a “load pickupwork”, and the forks 2 are placed in the load pickup position shown inFIG. 21(a). At this time, as the template T1 is read and an imagerecognition process of the mark M1 for pallet position detection iscarried out, the position of the mark M1 is acquired and the relativecoordinates (Xc, Yc, Zc) of the mark M1 and the camera 24 are acquiredbased on data (I, J, D) that is determined from that mark position. Theindividual controls amounts in the up and down and the left and rightdirections determined from the relative coordinates (Xc, Yc, Zc) areinstructed to the control valve 65. As a result, the forks 2 are placedin a state where they face the holes 41A of the pallet 41 as shown inFIG. 21(a). At this time, the forks 2 are positioned at a height Ht.

[0229] When the detected value (load weight) W from the load weightsensor 59 exceeds the threshold value Wo (W>Wo), on the other hand, itis determined that the load carrying work to be done next is a “loaddeposition work”, and the forks 2 are placed in the load depositionposition shown in FIG. 21(b). As the template T2 is read and an imagerecognition process of the mark M2 for rack position detection iscarried out, the position of the mark M2 is acquired and the relativecoordinates (Xc, Yc, Zc) of the mark M2 and the camera 24 are acquiredbased on data (I, J, D) that is determined from that mark position. Toplace the forks 2 in the load deposition position for the shelf plate42, the individual controls amounts in the up and down and the left andright directions determined from the relative coordinates (Xc, Yc, Zc)are instructed to the control valve 65. As a result, the forks 2 areplaced at a height Hp positioned above the shelf surface 42A by apredetermined distance AL as shown in FIG. 21(b).

[0230] Prior to that, when the height H of the forks 2 reaches 2 m orhigher and the activation standby mode is entered, the lifting controlof the camera is started. The camera lifting control is started by asignal input from the height sensor 58 when the height H of the forks 2reaches the height of 2 m. At this time, it is also determined based onthe detected value from the load weight sensor 59 whether or not theload carrying work to be done next is a load pickup work or a loaddeposition work. The height sensor 58 constitutes the detection meansthat outputs a signal to be used in determining if the start conditionfor the camera lifting control as aiding control is satisfied.

[0231] While the contents of the camera lifting control program isalmost the same as the routine in FIG. 20, inputting of a signal fromthe height sensor 58 indicating that the height 2 m has been reached inplace of the operation of the activation switch 38 is the condition tostart that program. When load weight W≧Wo, it is determined that a loadcarrying work to be done next is a “load pickup work” and the cameraunit 23 is placed in the storage position. When the load weight W<Wo, onthe other hand, it is determined that a load carrying work to be donenext is a “load deposition work” and the camera unit 23 is placed in thelift-down position. During this control, the electric actuator 61 isactivated only when it is necessary to move the camera unit 23.

[0232] The present embodiment has the following advantages.

[0233] (1) As the activation switch 38 is operated, the controller 45makes a decision on whether the load carrying work to be done next is aload pickup work or a load deposition work based on the detected valuefrom the load weight sensor 59. Then, control of the load handlingoperation is executed according to the type of the determined loadcarrying work. It is therefore possible to simplify the driver'soperations needed for a load carrying work as much as possible.

[0234] (2) When the height condition (H≧2 m) is met, camera liftingcontrol is started according to the signal from the height sensor 58 andthe camera unit 23 is placed in a position according to the type of theload carrying work. At this time, the controller 45 also makes adecision on whether the load carrying work to be done next is a loadpickup work or a load deposition work based on the detected value fromthe load weight sensor 59 and the camera unit 23 is placed in theposition according to the type of the determined load carrying work.This makes it unnecessary for the driver to notify the controller 45 ofwhich work the load carrying work to be done next is, so that the driverneed not perform any operation for the camera lifting control.

[0235] (3) The decision on whether or not there is a load 43 on theforks 2 is executed based on the detected value from the load weightsensor 59. Therefore, the sensor 59 is not easily broken and has a highreliability as compared with the structure that determines thepresence/absence of a load by means of a contact type switch, such as alimit switch.

[0236] Fifth Embodiment

[0237] The fifth embodiment will be described next. This embodiment isan example adapted to an automatic elevation unit equipped on anindustrial vehicle. The automatic elevation unit is a unit thatregisters height data of forks in a memory beforehand in associationwith an operation button and performs control to automatically lift upthe forks to a height corresponding to the button when operated.

[0238] As shown in FIG. 22, the instrument panel of the forklift 1 isprovided with a control panel 90 to place the forks 2 automatically in apredetermined position by a separate operation from the knob 35 of themulti lever 31.

[0239] The control panel 90 is comprised of a set key 91, three numberkeys 92 a to 92 c, a stocking key 93, a shipment key 94, a horizontalkey 95, a height limiting key 126, a stop key 197 and LEDs 198 providedadjacent to the individual keys.

[0240] The set key 91 is used when the height position of the forks 2 isset or when the height limit position of the forks 2 is set at the timeof doing shipment (load pickup) or stocking (load deposition) isperformed. The number keys 92 a to 92 c are used when the heightposition of the forks 2 is set or when the forks 2 are automaticallylifted up and can distinguish three height positions by numbers “1, 2,3”.

[0241] The stocking key 93 is used when the forks 2 are automaticallylifted up for lad deposition with a load placed on the forks 2 or whenthe height position is set. The shipment key 94 is used when the forks 2are automatically lifted up or when the height position is set at thetime of picking up a load stored at a predetermined height. The heightposition can be set distinguishably for each type of the load carryingwork. In this embodiment, the stocking key 93 and the shipment key 94are used only when the height position is set. Of course, the stockingkey 93 and the shipment key 94 can be eliminated by employing a methodof automatically setting the load deposition height to a position setapart above the load pickup height by a predetermined distance when anyof the number keys 92 a-92 c is selected and the load pickup height(load pickup height) is set.

[0242]FIG. 23 shows the electrical structure of the automatic elevationunit. In the present embodiment, the structural portions of the cameralifting control system and the image control system according to thefirst embodiment are omitted and the control panel 90 is connected tothe input side of the load handling control section 47 instead. Thestructural portion of the load handling system is the same as that ofthe first embodiment. Height sensor 58 can be used continuously todetect the height.

[0243] Although the height of the forks 2 slightly differs between aload deposition work and a load pickup work, the presence/absence of aload 43 on the forks 2 is detected based on the detected value from theload weight sensor 59. Then, it is determined that the load carryingwork is a load deposition work (stocking) in case of no load (loadweight W<threshold value Wo) and it is determined that the load carryingwork is a load pickup work (shipping) in case of the presence of a load(load weight W>threshold value Wo). The routine for determining the loadcarrying work is the same as the process of the flowchart in FIG. 20.The three number keys 92 a to 92 c, instead of the activation switch 38,constitute the start operation means, and the forks 2 are lifted up tothat one of the load pickup position and load deposition position,preset for each number key, which is determined by the detected loadweight.

[0244] The height limiting key 126 is used when the elevation height ofthe forks 2 is restricted at the time of operating the multi lever 31 orautomatic lifting. The individual LEDs 198 are controlled to be turnedon, or flickered by the controller 45 in association with the depressionof each key at the time of setting the height position, at the time ofan automatic lifting operation, at the time of setting the height limit,at the time of a horizontal stop operation, etc.

[0245] The load handling control section 47 of the controller 45 has amemory 47A. Target position data set through the control panel 90 isstored beforehand in the memory 47A. The target position data includesload deposition target position data and load pickup target positiondata for a single storage section of the rack 40.

[0246] In case where the forks 2 are lifted up to the target positionunder automatic lifting control, one of the number keys 92 a to 92 cwhich corresponds to that target position is depressed. The loadhandling control section 47 determines the presence/absence of a loadbased on the detected value from the load weight sensor 59, reads loaddeposition target position data corresponding to the depressed numberkey (one of 92 a-92 c) when it is determined that there is a load, andreads load pickup target position data corresponding to the depressednumber key (one of 92 a-92 c) when it is determined that there is noload.

[0247] The controller 45 activates the control valve 65 to drive thelift cylinders 15A, B in such a way as to move the forks 2 to the targetposition. While the lift cylinders 15A, 15B are being driven, the loadhandling control section 47 detects the height position of the forks 2every predetermined time based on the detection signal from the heightsensor 58.

[0248] When the forks 2 reach a height before the target position by apredetermined distance, the load handling control section 47 controlsthe current value of the electromagnetic control valve 66 to stop theprotracting actions of the lift cylinders 15A, 15B. Then, the forks 2are stopped in the target position. That is, it is stopped in the loaddeposition position (FIG. 21(b)) if there is a load 43 on the forks 2,and load deposition is carried out at that height. It is stopped in theload pickup position (FIG. 21(a)) if there is no load 43 on the forks 2and load pickup is carried out at that height. When the work is done,the forks 2 are moved from that height position. In case where it isfollowed by execution of automatic height control, for example, one ofthe number keys 92 a to 92 c is depressed next in that state unchangedto move the forks 2 to the next target position.

[0249] This embodiment has the following advantage.

[0250] As one of the number keys 92 a to 92 c is depressed, it ispossible to lift the forks 2 up with one of the “load pickup position”and “load deposition position” as the target position based on thedetected value from the load weight sensor 59. It is thereforeunnecessary for the driver to determine whether the work to be done nextis a load pickup work or a load deposition work and then select a key,but it is sufficient to depress one of the number keys 92 a to 92 cwhich is of the desired height.

[0251] The embodiment is not limited to the above-described one, but maybe embodied in the following forms.

[0252] The control contents of automatic load handling control is notlimited to the automatic fork positioning control or automatic liftingcontrol in each of the above-described embodiments. For example, thespeed of the load carrying apparatus may be controlled in such a waythat when it is determined, based on the detected load weight, that a“load pickup work” should be done, the lift-up speed of the loadcarrying apparatus is increased. When it is determined, based on thedetected load weight, that a “load deposition work” should be done, thelift-up speed of the load carrying apparatus is dropped.

[0253] The load detection means is not limited to the load weightsensor. This load detection means may be a limit switch to be providedon, for example, the forks. Alternatively, another sensor which detectsa load placed on the forks may be used as well. For example, anon-contact type sensor, such as a proximity sensor, which detects aload in a non-contact manner, may be used. Further, it is possible todetect the presence/absence of a load on the forks based on an imagepicked up by the camera. For example, means is provided for identifyingthe bottom shapes of the forks through an image. It is determined thatthere is no load (load pickup work) when the bottom shapes of the forkscan be identified, and it is determined that there is a load (loaddeposition work) when the bottoms of the forks are hidden by a load andthe bottom shapes of the forks cannot be recognized.

[0254] When a limit switch or a proximity switch is used, a signal to beoutput from the switch is an ON/OFF signal. When the output signal ofthe switch is an ON signal indicating the detection of a load, forexample, the decision means judges that it is a load deposition work andallows a load handling operation or an aiding operation according to theload deposition work to be carried out. When the output signal is an OFFsignal indicating that a load has not been detected, the decision meansjudges that it is a load pickup work and allows a load handlingoperation or an aiding operation according to the load pickup work to becarried out.

[0255] In the above-mentioned embodiment, camera lifting control isstarted by using a signal when the height condition (height H≧2 m) issatisfied, i.e., when the height sensor 58 detects the height H beingreached 2 m, as an instruction signal. Instead, the operation signal ofthe activation switch 38 may be used as instruction signal to startcamera lifting control. In this case, although the moving time of thecamera unit 23 delays automatic load handling control, a work can stillbe done with the operation of the activation switch alone.

[0256] In the above embodiment, automatic fork positioning control isstarted with the operation signal of the activation switch 38 as aninstruction signal. Instead, automatic fork positioning control may bestarted when it is determined that the start condition is satisfiedbased on the signal output from the sensor that serves as the detectionmeans. It is to be noted however that the sensor does not detect theoperation by a driver. For example, a given time (e.g., 0.3 sec) passesafter the forks are lifted up to a predetermined height and stopped, theCPU initiates the automatic fork positioning control. Then, theautomatic fork positioning control is executed targeting the markclosest to the stopped forks (one of the marks M1 and M2 whichcorresponds to the detected load weight). In this case, the detectionsection that detects the stop of the forks and the timer (counter) thatmeasures the time after the stop constitute the detection means.

[0257] The automatic elevation unit is constructed in such a way that aplurality of heights are stored in the memory beforehand and the targetheight at which the forks are to be lifted is specified by a buttonoperation. By way of contrast, control may be employed which places theforks at a rough height through the operation of the operation lever,automatically calculates the adequate position from a plurality oftarget positions stored in the memory and places the forks at theadequate target height. That is, the height sensor detects the height atwhich the forks are placed by the operation of the operation lever bythe driver, that height in the height data stored in the memory which isthe closest to the detected height is determined as the height intendedby the driver, and the lift cylinder is controlled in such a way as toplace the forks in the load pickup position or load deposition positionfor the height intended by the driver. While this structure does notperform automatic elevation, if the driver performs rough positioning ofthe forks at a temporary height and always operates the same singleswitch, decision on whether it is a load pickup work or a loaddeposition work is executed based on the detected value from the loadweight sensor and the forks are automatically positioned in the adequateposition according to the decision result.

[0258] Start instruction means is not limited to a switch, but a heightmay be designated with a voice input. For example, the driver can wear aheadphone type microphone and can inform the controller of informationdesignating the height, such as the number of shelves of the rack, in avoice input through the microphone.

[0259] A load handling operation after positioning a load carryingapparatus can also be controlled automatically. For example, a structurecan be employed which positions the forks and then automaticallyperforms a load pickup operation or a load deposition operation which isaccompanied with forward/backward movement of the forks. That is, if thedecision is load pickup, after the forks are positioned, the forks arereached to be inserted into the holes of a pallet, then lifted up by apredetermined amount (e.g., about 10 to 20 cm) to lift a load up, thenpulled backward to unload the load from the rack. If the decision isload deposition, on the other hand, after the forks are positioned, theforks are reached to push a load on the forks forward, then lifted downby a predetermined amount (e.g., about 10 to 20 cm) to place the load onthe rack, then pulled backward.

[0260] The use of the marks is not limited to the use of two types forload pickup and load deposition. A method that affixes a single mark forload pickup and load deposition in common to, for example, a shelfportion, can be used. When using this method to acquire the targetposition of the forks at the time of load pickup, for example, theposition of the shelf portion can be known by identifying the mark, andcomputing the height of the holes of a pallet placed on the shelfsurface from the position of the shelf portion to be the target positionof the forks.

[0261] It is not limited to making such a decision that it is loadpickup when there is a load and it is load deposition when there is noload. When the timing of the start switch is set to operate immediatelyafter a load pickup or load deposition, and when the operation of theload carrying apparatus is started by the start switch, it is possibleto decide that it is a load deposition work when there is a load and itis a load pickup work when there is no load. The operation of moving theforks backward may be automatically carried out when the activationswitch is operated after load pickup with the forks is completed and theoperation of moving the forks backward may be automatically carried outwhen the activation switch is operated after load deposition with theforks is completed.

[0262] Sixth Embodiment

[0263] The sixth embodiment of the present invention will be describedmainly on those that differ from the above-described embodimentsaccording to FIGS. 24 to 29. The present embodiment relates to a workmode switching apparatus, which sets the mode in accordance with a loadcarrying work. To simplify the description, same reference symbols aregiven to those constituents that are the same as those of each of theabove-described embodiments and their descriptions will be omitted.

[0264]FIG. 24 shows the state of a load carrying work by the forkliftequipped with the camera 24. The load carrying work for loads 43 iscarried out with the loads placed on pallets 41. A rack 40 where theloads 43 are to be placed has a multi-stage structure and some has anoverall height equal to or higher than the height of the forklift. Ifthe rack 40 has such a height, there may be a case where the drivercannot see the load carrying work from the driver's seat 9 at the timeof doing a load carrying work at a shelf plate 42 at a high place. Tosolve it, the forklift equipped with the camera 24 picks up the image ofan area in front of the forks 2 by the camera 24 and automaticallypositions the forks 2 based on the picked-up image, thereby supportingthe load carrying work.

[0265]FIG. 25 shows the driver's seat 9 of the forklift. An instrumentpanel is provided on the front portion of the driver's seat 9. Laid outon the instrument panel are the lift lever 96, the tilt lever 99, thereach lever 97, the side shift lever 98 and an accel lever 110. Theforks 2 are moved in the up and down direction by the operation of thelift lever 96, are moved in the forward and backward direction by theoperation of the reach lever 97, are moved in the left and rightdirection by the operation of the side shift lever 98, and are tilted bythe operation of the tilt lever 99. Those levers 96 to 98 are equivalentto load handling levers.

[0266] The lift lever 96 has a lever body 96 a and a grip portion (knob)111 is formed on the upper portion of the lever body 96 a. An activationswitch 112 is provided on a top surface 111 a of the grip portion 111and, as the activation switch 112 is depressed, the forks 2automatically start moving and are positioned. A mode changeover switch113 as switching means is provided on a side surface 111 b of the gripportion 111. The operation mode of automatic fork positioning control isswitched between a load pickup mode for picking up a load and a loaddeposition mode for placing a load in a predetermined position bydepressing the mode changeover switch 113.

[0267]FIG. 26 shows the control circuit of the forklift. The loadhandling operation aiding apparatus 20 has a controller 45, which hasthe image control section 46, the load handling control section 47 whichconstitutes control means and work mode setting means, the drivecircuits 48 and 49 and the solenoid drive circuit 50. The camera 24 isconnected to the input side of the image control section 46, and thedisplay device 28 and the speaker 51 are connected to the output side ofthe image control section 46, so that a video image is displayed on thescreen 28A (see FIG. 28 and FIG. 29) of the display device 28, based onthe video signal (image signal) from the camera 24, or a predeterminedannouncement is made from the speaker 51.

[0268] Meanwhile, the load handling control section 47 is connected withthe upper-limit position detection switch 52, the lower-limit positiondetection switch 53, potentiometers 96 a to 99 a of the levers 96 to 99,the activation switch 112, the mode changeover switch 113, the heightsensor 58, the load weight sensor 59, as detection means (load weightdetection means), the stroke sensor 73, the tilt angle sensor 60, etc.The load handling control section 47 is connected with the electricactuator 61 and load handling motor (electric motor) 62 via the drivecircuits 48, 49 and with the solenoids of various electromagneticselector valves 65 to 69 attached to the oil control valve 64 via thesolenoid drive circuit 50.

[0269] Based on signals from the individual potentiometers 96 a to 99 a,the load handling control section 47 performs current value control ofthe electromagnetic selector valves 65 to 69 and drive control of theload handling motor 62. As the load handling motor 62 is operated, theload handling pump (hydraulic pump) 70 is driven, thus supplying thehydraulic fluid to the oil control valve 65. Based on a signal at thetime when each of the levers 96 to 98 is operated, each of theelectromagnetic selector valves 65 to 69 corresponding to that operationis subjected to selection control. By this selection control, the reachcylinder 12, the lift cylinders 15A, 15B, the side shift cylinder 71,and the tilt cylinder 72 are controlled to perform the elevationoperation, reach operation, side shift operation, and tilt operation ofthe forks 2.

[0270] To acquire the deviation amount of the forks 2 at the time ofpositioning the forks, the image control section 46 executes imageprocessing based on image data acquired from the camera 24.

[0271] The image control section 46 has the display processing section75, the image processing section 76, the drawing display section 77, thedrawing data memory section 78 and the voice synthesizing section 79.The display processing section 75 outputs a video signal, input from thecamera 24, to the display device 28 in such a way that the image pickedup by the camera 24 is displayed on the screen. The image processingsection 76 receives the image data from the display processing section75, performs an image recognition process based on the image data andcalculates the coordinate positions of the marks M1 and M2 on thedisplay screen 28A of the display device 28 (the screen coordinatesystem shown in FIG. 27(a)).

[0272] Based on the results of the processing of the image processingsection 76, the drawing display section 77 displays the drawing of themoving target point mark 87 and a target line 120 (see FIG. 28 and FIG.29) or the like on the display screen 28A as drawing data stored in thedrawing data memory section 78. The drawing display section 77respectively displays, on the display screen 28 a, the “load pickupmode” when the operation mode is the load pickup mode and the “loaddeposition mode” when the operation mode is the load deposition mode.The voice synthesizing section 79 performs a voice synthesizing processfor voice announcement or the like and outputs a voice signal to thespeaker 51.

[0273] The image processing section 76 has the image recognitionprocessing section 81, the template memory section 82 and the screencoordinate position determining section 84. The load handling controlsection 47 has a real coordinate position calculating section (relativecoordinate computing section) 85 and a deviation amount computingsection (control amount calculating section) 86. The following willdescribe the contents of the processes performed by the imagerecognition processing section 81, the screen coordinate positiondetermining section 84, the real coordinate position calculating section85 and the deviation amount computing section 86 according to FIGS. 27and 28. The image recognition processing section 81, the template memorysection 82 and the screen coordinate position calculating section 84constitute sign position calculation means, and the real coordinateposition calculating section 85 and the deviation amount computingsection 86 constitute moving distance calculation means.

[0274] In case where the work mode is the load pickup mode and the markM1 is identified as shown in FIG. 27(a), the image recognitionprocessing section 81 performs matching on the two patterns P1, P1constituting the mark M1 at two locations using the template T1 andrecognizes each pattern P1, P1. Likewise, in case where the operationmode is the load deposition mode, each pattern P2, P2 is identifiedthrough matching on the two patterns P2, P2 constituting the mark M2 attwo locations using the template T2.

[0275] After pattern recognition, the screen coordinate positioncalculating section 84 computes coordinates (I₁, J₁), (I₂, J₂) of thecenter points (radial center points) of the individual patterns. P1, P1in the screen coordinate system. Then, the screen coordinate positioncalculating section 84 computes the barycentric coordinates (I, J) ofthe mark M1 and a center distance D of the patterns P1, P1 based onthose two coordinate values. In case where the operation mode is theload deposition mode, the barycentric coordinates of the mark M2 and thecenter distance of the patterns P2, P2 are computed in proceduressimilar to those for the mark M1.

[0276] Meanwhile, the real coordinate position calculating section 85performs geometric conversion using the values of the barycentriccoordinates (I, J) and the center distance D of the screen coordinatesystem to compute three-dimensional relative positional coordinates (Xc,Yc, Zc) with respect to the mark M of the camera 24 in a real coordinatesystem (XYZ coordinate system) shown in FIG. 27(b). The coordinates (Xc,Yc, Zc) of the camera 24 are computed by the equations (1) to (3).

[0277] Then, the deviation amount computing section 86 computes theamount of positional deviation of the forks 2 based on the relativepositional coordinates (Xc, Yc, Zc) of the camera 24 acquired in thereal coordinate system. Then, at the time the automatic fork positioncontrol is executed, the load handling control section 47 drives thelift cylinders 15A, 15B and the side shift cylinder 71 based on thedeviation amount calculated by the deviation amount computing section 86and executes positioning of the forks 2.

[0278]FIG. 28 shows the screen of the display device 28 at a time of aload pickup mode, and FIG. 29 shows the screen of the display device 28at a time of a load deposition mode. A moving target point 87 which willoverlap the mark M1 or M2 when the forks 2 are positioned is drawn onthe screen 28A. A target line 120 with an approximately cross shape isdisplayed on the screen 28A. The target line 120 is displayed on themark M1 when the work mode is a load pickup mode and is displayed on themark M2 when it is a load deposition mode.

[0279] The work mode is displayed on the upper left portion of thescreen 28A and “load pickup mode” or “load deposition mode” is displayedon the screen in accordance with the work mode at that time. Whenautomatic fork positioning control is executed by the depression of theactivation switch 112 of the lift lever 96 and positioning of the forks2 is completed, the moving target point mark 87 becomes matched with themark M1 at the time of a load pickup mode and the moving target pointmark 87 becomes matched with the mark M2 at the time of a loaddeposition mode.

[0280] A description will now be given of the operation of the thusconstituted work mode switching apparatus of an industrial vehicle.

[0281] First, assume that in case where a load deposition work isperformed, a load deposition work of placing a pallet 41 carrying a verylight load on a shelf plate 42. If the load is too light at this time,there may be a case where the load weight sensor 59 cannot detect theload weight of the load due to the matter of the sensor sensitivity.When the forks 2 are lifted down, buoyancy according to the descendingspeed (acceleration) acts on the load so that a value smaller than thereal load weight may be detected by the load weight sensor 59.Therefore, the work mode, which should normally be set to the loaddeposition mode, is set to the load pickup mode erroneously, displayingthe load pickup mode on the screen 28A of the display device 28 as shownin FIG. 28.

[0282] At the time of the load deposition work, the operator sees thework mode displayed on the screen 28A of the display device 28 andchecks if the work mode is correctly set for the load carrying work thatis being carried out. In this case, as the work mode is set to the loadpickup mode although a load deposition work is being performed, theoperator decides that the work mode should be switched and depresses themode changeover switch 113 of the lift lever 96. This switches the workmode to the load deposition mode from the load pickup mode and the workmode is set to the load deposition mode as shown in FIG. 29.

[0283] In case where a load pickup work is performed, when the forks 2are lifted up, a load according to the ascending speed (acceleration)acts on the forks 2 so that the load weight sensor 59 may detect thatload as a load weight. Therefore, the work mode, which should normallybe set to the load pickup mode, is set to the load deposition modeerroneously, displaying the load deposition mode on the screen 28A ofthe display device 28 as shown in FIG. 29. When the operator depressesthe mode changeover switch 113, however, the work mode is switched tothe load pickup mode from the load deposition mode and the work mode isset to the load pickup mode as shown in FIG. 28.

[0284] In the structure that automatically sets the work mode based onthe load weight acquired from the load weight sensor 59, therefore, aload weight different from the actual one may be detected at the time anextremely light load is placed on the forks 2 or the forks 2 are liftedup or down. Even in case where the work mode does not coincide with theactual load carrying work due to those causes, operating the modechangeover switch 113 provided on the lift lever 96 can set the workmode to the correct mode according to the load carrying work.

[0285] This embodiment therefore has the following advantages.

[0286] The mode changeover switch 113, which switches the work modemanually when the load pickup mode or load deposition mode isautomatically set as the work mode based on the load weight acquiredfrom the detected value from the load weight sensor 59 and the set workmode is in error, is provided on the lift lever 96. There is a casewhere the relatively low detection sensitivity of the load weight sensor59 prevents the load weight sensor 59 from detecting the load when aload is extremely light, or the acceleration at the time of lifting theforks 2 up or down causes the weight of a load to be detected lighter orheavier than it really is, so that the load weight sensor 59 erroneouslyrecognizes the load.

[0287] Even if the work mode is erroneously set due to the erroneousrecognition by the load weight sensor 59, however, the work mode can beset to the correct mode according to the load carrying work by operatingthe mode changeover switch 113.

[0288] As the set work mode is displayed on the screen 28A, it ispossible to determine if the set work mode is correct with respect tothe load carrying work that is actually undergoing by checking the workmode displayed on the screen 28A.

[0289] As the mode changeover switch 113 is provided on the grip portion111 of the lift lever 96, the switch 113 can be operated without settinga hand free of the lift lever 96, so that the working efficiency at thetime of automatic fork positioning control can be improved.Particularly, movement of the forks 2 up and down is often done by usingthe lift lever 96 and the provision of the switch 113 on the lift lever96 can ensure a smooth work of switching the work mode.

[0290] Seventh Embodiment

[0291] The seventh embodiment will be described next according to FIGS.30 to 32. Like the fifth embodiment, this embodiment is an exampleadapted to an automatic elevation unit equipped on an industrialvehicle.

[0292] Two LEDs 121 and 122 are provided on the control panel 90according to this embodiment shown in FIG. 31 in addition to variouskeys, etc. provided on the control panel 90 shown in FIG. 22.

[0293]FIG. 32 shows the electrical structure of the automatic elevationunit. The structural portions of the camera lifting control system andthe image control system according to the sixth embodiment are omittedand the control panel 90 is connected to the input side instead. Thestructural portion of the load handling system is the same as that ofthe sixth embodiment. A sensor that can continuously detect the heightis used as the height sensor 58.

[0294] Although the height of the forks 2 slightly differs between aload deposition work and a load pickup work, the presence/absence of aload on the forks 2 is detected based on the detected value from theload weight sensor 59. Then, it is determined that the load carryingwork is a load deposition work (stocking) in case of no load (loadweight W<threshold value W₀) and it is determined that the load carryingwork is a load pickup work (shipping) in case of the presence of a load(load weight W>threshold value W₀). As the three number keys 92 a to 92c are depressed, the forks 2 are lifted up to that one of the loadpickup position and load deposition position, preset for each numberkey, which is determined by the detected load weight.

[0295] The height limiting key 126 is used when the elevation height ofthe forks 2 is restricted at the time of operating the lift lever 96 orautomatic lifting. The individual LEDs 121, 122 and 198 are controlledto be turned on, or flickered by the controller 45 in association withthe depression of each key at the time of setting the height position,at the time of an automatic lifting operation, at the time of settingthe height limit, at the time of a horizontal stop operation, etc.

[0296] The load handling control section 47 of the controller 45 has amemory 123. Target position data set through the control panel 90 isstored beforehand in the memory 123. That is, the target position datais data set according to the number keys 92 a to 92 c for loaddeposition and load pickup and load deposition target position data andload pickup target position data are set with respect to the individualshelf plates 42 of the rack 40, which have different heights.

[0297] In case where the forks 2 are lifted up to the target positionunder automatic lifting control, one of the number keys 92 a to 92 cwhich corresponds to that target position is depressed. The loadhandling control section 47 determines the presence/absence of a loadbased on the detected value from the load weight sensor 59, reads loaddeposition target position data corresponding to the depressed numberkey 92 a-92 c when it is a load deposition mode, and reads load pickuptarget position data corresponding to the depressed number key 92 a-92 cwhen it is a load pickup mode. The control valve 64 is actuated in sucha way as to move the forks 2 to the target position. While the liftcylinders 15A, 15B are being driven, the load handling control section47 detects the height position of the forks 2 every predetermined timebased on the detection signal from the height sensor 58.

[0298] When the height position of the forks 2 reaches a height beforethe target position by a predetermined distance, the load handlingcontrol section 47 controls the current value of the electromagneticcontrol valve 65 to stop the protracting actions of the lift cylinders15A, 15B, causing the forks 2 to stop in the target position. That is,when a load 43 is on the forks 2 as shown in FIG. 30(a), forks 2 arestopped in an upper position apart from the shelf surface 42 a by ΔL1and load deposition is carried out at that height. When there is no load43 on the forks 2 as shown in FIG. 30(b), the forks 2 are stopped in anupper position apart from the shelf surface 42 a by ΔL2 and load pickupis carried out at that height. When the work at that height is finished,the forks 2 are moved from that height. In case where it is followed byexecution of automatic height control, for example, one of the numberkeys 92 a to 92 c is depressed directly to move the forks 2automatically to the next target position.

[0299] The load weight sensor 59 might detect a false value when theload is extremely light and the load weight sensor 59 may not be able todetect the weight of the load due to the sensor sensitivity, or when theforks 2 are lifted up or down and buoyancy or acceleration acts on theload. Therefore, the work mode is erroneously set with respect to theactual load carrying work and the load pickup mode is set, even though aload is placed on the forks 2, and the LED 122 for load pickup emitslight or the load deposition mode is set, even though there is no loadon the forks 2, and the LED 121 for load deposition emits light.

[0300] In case where the LED in the two LEDs 121 and 122 which emitslight on the control panel 90 does not correspond to the actual loadcarrying work, however, the operator can switch the work mode bydepressing the mode changeover switch 113 of the lift lever 96. In casewhere the load pickup mode is set even though a load is placed on theforks 2, or in case where the load deposition mode is set even thoughthere is no load on the forks 2, therefore, depressing the modechangeover switch 113 sets the work mode to the correct mode accordingto the load carrying work.

[0301] This embodiment can have the same advantages as the sixthembodiment as well as the following advantage.

[0302] As one of the number keys 92 a to 92 c is depressed, the forks 2are lifted up with the “load pickup position” as the target position inload pickup mode and the forks 2 are lifted up with the “load depositionposition” as the target position in load deposition mode. It istherefore unnecessary for the operator to determine whether it is loadpickup or load deposition and then select a key to be operated, but theforks 2 can be automatically lifted up to the desired position by merelydepressing one of the number keys 92 a to 92 c which is equivalent tothe desired height.

[0303] The embodiment is not limited to those described above, but maybe modified in the following forms.

[0304] In the sixth and seventh embodiments, works that areautomatically controlled by an industrial vehicle are not limited to awork of positioning the forks 2 with respect to the mark M1 (M2) and awork of positioning the height of the forks 2 by the automatic elevationunit. For example, an operation of performing the reach operation of theforks 2 to unload a load on the rack 40 or an operation of placing aload on the forks 2 in the rack 40 may be automated. And, a plurality ofwork modes to be set then may be manually switched by the modechangeover switch 113.

[0305] In the sixth and seventh embodiments, the work modes are notlimited to the load pickup mode and the load deposition mode, but may beany modes necessary for various works, such as a load carrying work anda transportation work. The detection means is not limited to the loadweight sensor 59, and may be anything which acquires a detected valuenecessary at the time of setting a mode other than the load pickup modeand load deposition mode.

[0306] In the sixth and seventh embodiments, the work modes are notlimited to two, the load pickup mode and the load deposition mode, butmay be three or more with predetermined modes added to those two. Inthis case, the work mode may be switched in order every time the modechangeover switch 113 is depressed once or exclusive switches may beprovided for the individual modes.

[0307] In the sixth and seventh embodiments, the work mode set thenshould not necessarily be notified by the display device 28 and the LEDs121, 122 for notification. That is, the work mode may be switched byoperating the mode changeover switch 113 in case where this type ofnotification means is not installed, the work mode is checked visuallyand the work mode differs from the actual load carrying work as a resultof the visual check.

[0308] In the sixth and seventh embodiments, both of the function ofpositioning the forks 2 through an image recognition process and theautomatic elevation unit may be mounted on the forklift or one of themmay be mounted.

[0309] In the sixth and seventh embodiments, the levers may be a multilever singularly capable of doing a reach operation, a lift operation, aside shift operation and a tilt operation, instead of assigning a singlefunction lever by lever. The mode changeover switch 113 may be providedin a predetermined position of this multi lever.

[0310] In the sixth and seventh embodiments, the mode changeover switch113 as the switching means is not limited to provision on the lift lever96 but may be provided on the tilt lever 99, reach lever 97, side shiftlever 98 or the like. It may also be provided on a portion other thanthe lever, such as the instrument panel.

[0311] In the sixth and seventh embodiments, the mode changeover switch113 as the switching means is not limited to a depression button switchtype, but may be any type that can switch the work mode, such as a levertype or a touch panel type.

[0312] In the sixth and seventh embodiments, the switching means is notlimited to a single switch that switches the work mode between the loadpickup mode and the load deposition mode. That is, a switch for the loadpickup mode and a switch for the load deposition mode may be providedseparately.

[0313] In the sixth and seventh embodiments, the load weight detectionmeans is not limited to the load weight sensor 59 that outputs adetected value according to the load weight, but may be a sensor whichdetects the presence/absence of a load, such as a limit switch or aproximity switch.

[0314] In the sixth and seventh embodiments, the actuator is not limitedto various cylinders 12, 15, 71, and 72 that are driven at the time ofexecuting automatic fork positioning control but may be, for example, amotor or the like.

[0315] In the sixth and seventh embodiments, the notification means isnot limited to the display device 28 and the LEDs 121, 122 that providevisual notification, but the set work mode may be audibly notified byoutputting sounds from the speaker 51. In this case, the speaker 51 isequivalent to the notification means. Further, visual notification isnot limited to character display but a lamp, such as a LED, may beturned on and left so.

[0316] In the sixth embodiment, the deviation amount of the forks 2 maybe calculated by performing an image recognition process with the pallet41 or rack 40, for example, as a sign and acquiring the real coordinateposition of the camera 24 based on the processing result.

[0317] In the seventh embodiment, the operator may operate the liftlever 96 to lift the forks 2 up to a predetermined position, thendepress a number key to lift them to the desired height position. Inthis case, the height positions of the forks 2 are detected by theheight sensor one after another, the height to the target heightposition from the point of time at which the number key has beendepressed is acquired and the forks 2 are lifted up by that amount.

[0318] Eighth Embodiment

[0319] The eighth embodiment of the present invention will be describedmainly on those that differ from the first embodiment according to FIGS.33 to 39. Conventionally, at the time of moving an industrial vehicleclose to a load handling target, such as a pallet 41, if it was foundthat the forks 2 could not be inserted in the holes 41A of the pallet 41after moving the forklift shown in FIG. 39(a) close to the load handlingtarget, the driver performed the following operation. That is, it wasnecessary to steer the steering wheel 10 while temporarily moving theforklift back, then steer the steering wheel 10 again to pull over asshown in FIG. 39(b) and place the vehicle in the correct position shownin FIG. 39(c).

[0320] According to the present embodiment, by way of contrast, at thetime of moving an industrial vehicle close to a load handling target,such as a pallet, the position of the load handling target is detectedbeforehand and an adequate instruction or guiding notification is givento the driver so that a working loss can be avoided.

[0321] The image control section 46 in the present embodiment performsan image recognition process (template matching process) to recognize amark from an image, grasps the position of a load handling target fromthe position of the mark in the screen coordinate system on the screen,and further performs a notification process to guide the course of thevehicle so that the load handling target is caught by the forks 2. Inthe notification process, a method of displaying an instruction guide onthe screen of the display device 28 and a method of giving notificationwith voice guidance from the speaker 51 are used together as a method ofguiding the course of the vehicle. It is of course possible to use oneof the notification methods.

[0322] As shown in FIGS. 33 and 34, at the time of positioning the forks2 in this embodiment, a target mark 87 is displayed on the screen 28A ofthe display device 28 at the target position to which the mark M1, M2should be moved. As the forks 2 are moved in such a way that the centerpoint (moving target point) of the target mark 87 coincides with thecenter point of the mark M1 affixed to the pallet 41, the forks 2coincide with the insertion holes 41A. As the forks 2 are moved in sucha way that the target mark 87 coincides with the mark M2 affixed to theshelf plate 42, on the other hand, the forks 2 are placed in the loaddeposition position above the shelf surface 42A by about 10 to 20 cm.

[0323] As the camera 24 is placed in the center portion in the vehicle'swidthwise direction between a pair of forks 2, the Y-directionalcomponent (see FIG. 3) of the moving target point is identical to thecoordinate Yc of the camera 24. As mentioned above, the coordinates ofthe camera 24 are expressed by (Xc, Yc, Zc). Therefore, the difference(deviation) of the Y-directional component between the moving targetpoint and the center point (origin) of the mark M1 is equal to thecoordinate Yc. If the sideway deviation Yc is greater than zero (Yc>0),the forks 2 are deviated leftward on the screen 28A (i.e., the mark isin the rightward), If Yc<0, the forks 2 are deviated rightward on thescreen (i.e., the mark is in the leftward), and if Yc=0, there is nosideway deviation of the forks 2.

[0324] If the forks 2 are in a side-shifted state, the value Yc includesthat side shift amount Sshift. First, it is therefore necessary toacquire the Y-directional deviation amount Yr between the moving targetpoint and the mark on the assumption that the forks 2 are notside-shifted and is positioned in the vehicle's widthwise center. Thisdeviation amount Yr is computed from

Yr=Yc−Sshift.

[0325] It is assumed that when the forks 2 are shifted to the right, theside shift amount takes a value of Sshift<0, and when the forks 2 areshifted to the left, the side shift amount takes a value of Sshift>0.The screen 28A in FIG. 33 shows a case where the forks 2 are placed inthe vehicle's widthwise center and the side shift amount Sshift=0.

[0326] When the deviation amount |Yr| has a value within a maximum sideshift amount Smax, the forks 2 can be positioned to a load handlingtarget by side-shifting the forks 2. When the deviation amount |Yr|exceeds Smax, however, the load handling target can no longer be caughtby the forks 2 even if the forks 2 are side-shifted. In this respect, aset value S (≦Smax), which is the same as the maximum side shift amountSmax, or a smaller value S with a slight margin, is set beforehand, andwhen |Yr|>S (S=150 mm in this example) is satisfied, it cannot be copedwith side shifting and the driver is informed by a pull-over instructionthrough the display on the screen 28A and by voices from the speaker 51.At this time, the pull-over direction is determined by thepositive/negative of the value of Yc. That is, when Yc>0, it isdetermined that the forks 2 are shifted leftward and should be pulledover rightward, and when Yc<0, it is determined that the forks 2 areshifted rightward and should be pulled over leftward. An instructionguide 88 as shown in FIG. 33 (the diagram shows a case of apull-over-to-the-right instruction) is displayed on the screen 28A. InFIG. 33, the mark M2 is omitted.

[0327] The display position determining section 84 performs thefollowing process to determine the display position of the instructionguide 88. When Yc>0, it is determined that the forks 2 are deviatedleftward and a load handling target is positioned on the right-hand halfof the screen as in FIG. 33, and the left-hand area of the screen isdecided as the display position of the instruction guide 88. When Yc<0,on the other hand, it is determined that the forks 2 are deviatedrightward and the load handling target is positioned on the left-handhalf of the screen as in FIG. 33, and the right-hand area of the screenis decided as the display position of the instruction guide 88. When theinstruction guide 88 is displayed on the right-hand side of the screenor the left-hand side of the screen, the respective display position isdetermined previously. When the deviation amount |Yr| becomes |Yr|≦S(150 mm in this example), the display of the instruction guide 88disappears.

[0328] If the display position is determined when the display of aninstruction guide is needed, the display position determining section 84sends data of the instruction guide to the drawing display section 77.The instruction guide 88 is comprised of an arrow figure directed in thepull-over direction, a numeral “(numeral) mm” of the pull-over distanceto be displayed in the arrow figure and a sequence of characters “pullover”. The value of the actual deviation amount |Yc| comes into thevalue of the pull-over distance.

[0329] Stored in the drawing data memory section 78 are figure data oftwo types of instruction guides and font data, which shows the pull-overdistance |Yc|. There are two types of figure data prepared: one is afigure for pull-over to the right (see FIG. 33) and the other is afigure for pull-over to the left (a figure with the opposite directionof the arrow to that of the figure in FIG. 33). The drawing displaysection 77 reads necessary figure data and font data from the drawingdata memory section 78 according to an instruction from the displayposition determining section 84 and displays the instruction guide 88 asshown in FIG. 33 in a predetermined position in such a way as to overlapthe picked-up image. Further, when the display of the instruction guideis needed, the display position determining section 84 outputs aninstruction of voice guidance according to that content to the voicesynthesizing section. The image processing section 76 is comprised of amicrocomputer and program data stored in the memory (ROM) or the like.The drawing display section 77 and the drawing data memory section 78are constituted by a drawing control gate array and a drawing VRAM.

[0330] In the present embodiment, a guide displaying process routineillustrated in a flowchart in FIG. 35 is stored in the memory of theimage processing section 76 as a process the microcomputer of the imageprocessing section 76 executes to display an instruction guide.

[0331] The following will describe the instruction guide displayingprocess that is executed by the image processing section 76 inaccordance with the flowchart illustrated in FIG. 35.

[0332] First, in step (hereinafter simply written as “S”) 110, the imageprocessing section 76 executes image processing (mark identifyingprocess). That is, if it is a load pickup mode, a process of identifyingthe mark M1 using the template T1 is executed, whereas if it is a loaddeposition mode, a process of identifying the mark M2 using the templateT2 is executed. Thus, position data I, J and D values of the mark areacquired.

[0333] In the next S120, the relative position change Yr between theforks and the target is calculated. That is, the relative position (Xc,Yc, Zc) is acquired based on the position data I, J and D values of themark. Then, Yr (=Yc−Sshift) is calculated from the Yc value.

[0334] In S130, it is determined whether or not |Yr|>S is satisfied. If|Yr|>S is not satisfied, this routine is terminated, whereas if |Yr|>Sis satisfied, the process proceeds to S140.

[0335] In S140, a pull-over instruction is performed. That is, if Yc>0,a pull-over-to-the-right instruction as shown in FIG. 33 is displayed inthe left-hand area of the screen and if Yc<0, a pull-over-to-the-leftinstruction is displayed in the right-hand area of the screen. At thistime, notification of pulling over is also made in voice from thespeaker 51.

[0336] Assume that while facing a load handling target at apredetermined distance (e.g., 2 to 3 m), the forklift 1 is greatlydeviated to the left in the vehicle's widthwise direction with respectto the load handling target as shown in FIG. 36(a). At this time, theinstruction guide 88 instructing pulling over in the rightward directionis displayed on the screen 28A as shown in FIG. 33, and an instructionfor pulling over in the rightward direction is given in voice guidance.And, the driver steers the steering wheel 10 to the right according tothe instruction to pull over to the right, and when the vehicle iscorrected to the point where no further pulling over is needed, theinstruction guide 88 disappears from the screen. This can reduce thefrequency of occurrence of the inconvenience that after the forklift 1are moved close to the load handling target, the wheel of the forklift 1should be quickly turned due to a large sideway positional deviationbetween the forks 2 and the load handling target. After the instructionguide 88 is gone, the forks 2 can be inserted into the insertion holes41A of the pallet 41 by using side shifting as needed.

[0337] The display position of the instruction guide 88 is set to theleft side of the screen when it is “pull-over-to-the-right” and is setto the right side of the screen when it is “pull-over-to-the-left”. Thatis, the display position of the instruction guide 88 is set in an areaopposite to the position where the mark M is displayed with respect tothe moving target point. In case of the pull-over-to-the-right where thevehicle body is shifted to the left, for example, the instruction guide88 is displayed on the left-hand side, so that the load handling targetis not blocked by the display of the instruction guide 88. As the loadhandling target on the screen comes closer to the center of the screenby the pulling over of the vehicle, the instruction guide 88 disappearsso that the image of the load handling target is less blocked by theinstruction guide 88 displayed on the screen 28A.

[0338] When the activation switch 38 of the multi lever 31 is operatedin a state in which the forks 2 can be inserted in the insertion holes41A of the pallet 41 by using side shifting, automatic fork positioningcontrol is initiated. The control amounts are acquired from the relativepositional coordinates (Xc, Yc, Zc), and the positioning of the forks 2is executed by controlling the current values of the electromagneticproportional valve 65 for lifting and the electromagnetic proportionalvalve 68 for side shifting via the solenoid drive circuit 50 based onthe control amounts and by driving and controlling the lift cylinders 15and the side shift cylinder 71 as needed.

[0339] The present embodiment has the following advantages.

[0340] Before approaching a load handling target, the position of theload handling target on the image picked up by the camera 24 beforehandis grasped by using an image recognition process and the deviationamount between the forks 2 and the pallet 41 is calculated. Then, whenthe deviation amount |Yr| exceeds the set value S, the pull-overinstruction guide 88 is displayed on the screen 28A. If the vehicle isallowed to approach the load handling target while being pulled overaccording to the instruction guide 88, therefore, the vehicle can beplaced in the position where the instance it approaches the loadhandling target, the forks 2 are insertable in the insertion holes 41Aof the pallet 41.

[0341] The instruction guide 88 instructs not only the pull-overdirection but also the pull-over distance. As the direction and thedistance in and by which pulling over should be made are known,therefore, the driver can correctly place the vehicle with respect tothe load handling target by following the instruction guide 88.

[0342] If and only if even side-shifting the forks 2 cannot cause theforks 2 to be inserted into the insertion holes 41A of the load handlingtarget (pallet 41), the instruction guide 88 is displayed on the screen28A. Therefore, the vehicle can be directly driven without being pulledover when side shifting can cope with it.

[0343] The timing to set off the display of the instruction guide 88 iswhen the deviation amount |Yr| falls within the set value S. Therefore,pulling over according to the instruction of the instruction guide 88can correct the vehicle to the position where side shifting can copewith it.

[0344] The instruction guide 88 is displayed on the screen 28A at theposition to avoid the load handling target. That is, the instructionguide 88 is displayed to the left on the screen when the load handlingtarget is shifted to the right on the screen 28A, and the instructionguide 88 is displayed to the right on the screen when the load handlingtarget is shifted to the left on the screen 28A. Thus, the display ofthe instruction guide 88 does not block the display for positioning theload handling target displayed on the screen 28A.

[0345] A pull-over instruction is notified in voice from the speaker 51.Even when the driver is not watching the screen 28A, therefore, as thedriver listens to the voice instruction, the driver can know beforehandthat the vehicle body is shifted in the vehicle's widthwise directionwith respect to the load handling target. Therefore, it is possible toprevent the quick turn of the wheel of the vehicle originated fromoverlooking the instruction guide 88 on the screen 28A.

[0346] As the method of detecting the position of the load handlingtarget through an image recognition process using the image picked up bycamera 24, is adopted, the position of the load handling target cansurely be detected even at a distance apart from the load handlingtarget by several meters.

[0347] By using the camera 24 and display device 28 provided to supporta load carrying work at a high place, the instruction guide 88 isdisplayed on the screen 28A of the display device 28. It is thereforepossible to easily add the pull-over instruction notifying functionmerely by adding software.

[0348] Ninth Embodiment

[0349] The controller 45 in this embodiment determines how far toapproach when the forklift 1 is caused to approach a load handlingtarget, and instructs it to the driver. For example, after the vehicleis moved close to the load handling target, the load handling apparatus11 is extended such that the forks 2 are inserted into the insertionholes 41A of the pallet 41. At this time, if the vehicle is notsufficiently close to the load handling target, the vehicle must bemoved forward after extending the load handling apparatus 11. To avoidsuch an inconvenience, an instruction is output onto the screen 28Auntil the vehicle comes as close to the load handling target as needed.The forklift 1 is provided with a reach sensor (not shown) that detectsa reach amount, and the controller 45 calculates the reach amount from asignal input from the reach sensor.

[0350] In the present embodiment, a guide displaying process routineillustrated in a flowchart in FIG. 37 is stored in the controller 45 asa process the controller 45 executes to display an instruction guide.The following will describe the instruction guide displaying processthat is executed in accordance with this flowchart.

[0351] First, in S210, the controller 45 executes image processing (markidentifying process). That is, if it is a load pickup mode, a process ofidentifying the mark M1 using the template T1 is executed, whereas if itis a load deposition mode, a process of identifying the mark M2 usingthe template T2 is executed. Thus, position data I, J and D values ofthe mark are acquired.

[0352] In the next S220, the controller 45 calculates the relativedistance Xr between the forks and the target. That is, the relativeposition (Xc, Yc, Zc) is acquired based on the position data I, J and Dvalues of the mark. Then, Xr(=−Xc−Rshift) is calculated from the Xcvalue. Here, Rshift is the reach amount that is grasped based on thedetection signal from the reach sensor.

[0353] In S230, the controller 45 determines whether or not Xr>R issatisfied. If Xr>R is not satisfied, this routine is terminated, whereasif Xr>R is satisfied, the process proceeds to S240. Here, R is a setvalue equal to or smaller than the maximum reach amount.

[0354] In S240, the controller 45 makes a forward drive instruction.That is, an instruction guide to instruct the forward driving isdisplayed on the screen 28A and the forward driving is instructed alsoin voice from the speaker 51.

[0355] If the vehicle is stopped according to the display on the screen28A and an instruction guide made in voice at the time of moving thevehicle closer to the load handling target, it is possible to reach theforks 2 from the stop position and surely catch the load handlingtarget. This can avoid a wasteful work of moving the vehicle forwardagain by a short distance because of an insufficient forward movement ofthe vehicle after the operation enters the reach operation.

[0356] Tenth Embodiment

[0357] This embodiment determines beforehand whether the forks 2 reachthe height of the target or not and, when it is determined that it isnot reachable, the driver is given a notification to that effect. Theinstrument panel is provided with a height check switch 130 (see FIG. 4)which is operated at the time of checking whether the height of thetarget rack exceeds the limit of a maximum height Hmax of the forklift1. When there are plural marks shown on the screen 28A, with the topmostmark M1 (M2) taken as a target, the target height is calculated in loadpickup mode as the height to the insertion holes 41A of the pallet 41corresponding to the mark M1 and the target height is calculated in loaddeposition mode as the deposition height to the shelf plate 42corresponding to the mark M2.

[0358] At the time of calculating the target height, first, the topstage of the rack 40 is picked up by the camera 24 at the position at adistance from the rack 40. In this case, a sufficient distance from therack 40 may be taken or the forks 2 may be lifted up to make it easierto show the topmost stage of the rack. When the height check switch 130is operated in that state, the controller 45 aims at the mark M1 (M2) atthe topmost position in the image shown on the screen 28A. The heightsensor 58 can be used continuously to detect the height.

[0359] In the present embodiment, a height checking routine illustratedin a flowchart in FIG. 38 is stored in the controller 45 as a processthe controller 45 executes to display for height checking. The followingwill discuss the height checking process that is executed according tothis flowchart.

[0360] First, in S310, the controller 45 executes image processing (markidentifying process). That is, if it is a load pickup mode, a process ofidentifying the mark M1 using the template T1 is executed, whereas if itis a load deposition mode, a process of identifying the mark M2 usingthe template T2 is executed. And, position data I, J and D values of themark are acquired.

[0361] In the next S320, the controller 45 calculates the height Hr ofthe target. That is, the relative position (Xc, Yc, Zc) is acquiredbased on the position data I, J and D values of the mark. Then, thetarget height Hr (=Zc+Hf) is calculated using the Zc value and theheight Hf obtained from the detection signal from the height sensor 58.

[0362] In S330, the controller 45 determines whether or not Hr>Hmax issatisfied. If Hr>Hmax is not satisfied, this routine is terminated,whereas if Hr>Hmax is satisfied, the process proceeds to S340.

[0363] In S340, the controller 45 notifies that load handling isimpossible due to an insufficient height. That is, notice is displayedon screen 28A and by voice from speaker 51 that the forks 2 do not reachthe target and the height is insufficient.

[0364] If the load handling target to be an aim is shown on the screen28A and the height check switch 130 is manipulated, the target height isdetected and it is determined whether or not the forks 2 reach thetarget, and if the forks 2 do not reach the target, notification to thateffect (insufficient height) is made through the display on the screen28A and voices from the speaker 51. Therefore, the driver can knowbeforehand that the load handling target should be changed before goingto a work of actually approaching the rack or lifting the forks 2 up. Itis thus possible to avoid a wasteful work of changing the load handlingtarget after actually approaching the rack 40 or lifting the forks 2 upand finding out that the target is not reachable.

[0365] The present embodiment is not limited to what is described above,but may be embodied in the following forms.

[0366] In the eighth embodiment, the timing to set off the display ofthe instruction guide 88 is set to when |Yr|≦S (e.g., S=150 mm) issatisfied and the vehicle is guided to the position where side shiftingcan cope with it. In contrast to that, the timing to set off the displayof the instruction guide 88 may be set to |Yr|≦S (e.g., S=within 40 mm)so that the vehicle can be pulled over to the position where the forks 2can be inserted directly into the insertion holes 41A of the pallet 41without being side-shifted. In this case, if the vehicle is pulled overaccording to the instruction guide 88, the forks 2 can be inserteddirectly into the insertion holes 41A of the pallet 41 without beingside-shifted. This can eliminate the troublesome side shiftingoperation, further improving the work efficiency.

[0367] The contents to be notified by the notification means is notlimited to the pull-over direction and distance. The direction alone maybe notified. For example, when the pull-over direction is notified andthe position of the vehicle is corrected within the range where the loadhandling target can be caught by mere movement of the forks, thenotification of “OK” may be given or notification may be ended. Insteadof the pull-over direction, the moving direction may be instructed; forexample, the angle of the arrow direction of the instruction guide maybe changed in accordance with the course.

[0368] The detection means is not limited to a camera. It may be asensor which can detect the position of the load handling target. Forexample, a plurality of laser beams may be irradiated horizontally froma predetermined height of a rack while an industrial vehicle may beequipped with plural sensors in the vehicle's widthwise direction at thesame height as the irradiation height of the laser beams, the positionof the industrial vehicle may be calculated from the layout of those ofthe plural sensors which have received the laser beams, and thepull-over direction and distance may be instructed based on thecalculated position.

[0369] Further, in case of using a camera, the camera need not beprovided on the industrial vehicle. A method may be employed which thecamera is set on the ceiling of a warehouse, the position of theindustrial vehicle is calculated based on image data picked up by thatcamera and the controller of the industrial vehicle is informed of thecalculated vehicle position data by radio communication. The controllercalculates the pull-over direction and distance to be corrected, basedon the received vehicle position data and notifies the driver throughdisplay or in voice.

[0370] It is possible to set the position arbitrarily to display aninstruction guide on the screen of the display device. For example, itis possible to calculate the position of a mark, predict and calculate awork area on the screen from the position of the mark, and display aninstruction guide in a display position where the predicted work area isavoided.

[0371] The path of a course (drive line) to guide the vehicle may bedisplayed on the screen 28A.

[0372] Instead of instructing the steering direction by a figure, suchas an arrow, on the screen of the display device, the direction in whichthe steering is manipulated may be displayed in a sequence ofcharacters. For example, a sequence of characters, such as “pull over tothe right” or “pull over to the left”, is displayed.

[0373] The instruction sign is not limited to the shape that hasdirectivity, such as an arrow. A mark with a shape that does not havedirectivity (a circle, rectangle, or the like) may be used and thepull-over direction may be notified by the position on the screen wherethat mark is to be displayed. In this case, the driver can see that itis an pull-over-to-the-left instruction if the mark is displayed on theleft-hand side of the screen and it is a pull-over-to-the-rightinstruction if the mark is displayed on the right-hand side of thescreen.

[0374] A structure may be such that two types of indicator lights, suchas lamps or LEDs, are provided on the instrument panel in the driver'scab and the direction to correct the vehicle is indicated by turning onthe indicator lights. In this case, the indicator lights constitute thenotification means.

[0375] Although the mark for position detection of a load handlingtarget is a radial figure, it is not limited to such a figure. It may bea simple figure, such as a circle (∘), a rectangle (

) or a triangle (Δ). The position detection of a load handling targetmay be carried out by performing pattern matching using multipletemplates, or an image recognition method other than the patternmatching may be used to detect the position of a load handling target.

[0376] The eighth to tenth embodiments are not limited to an industrialvehicle that has forks (load carrying apparatus) provided movable in thevehicle's widthwise direction. They can be adapted to a forklift thatdoes not have the side shifting function. In this case, if notificationto guide the course of the forklift in such a way as to insert the forksinto the holes of a pallet is designed to be made through display or invoice or the like, the same advantages as those of the above embodimentscan be obtained.

[0377] The direction indicating sign, such as the instruction guide 88,which indicates the direction to guide the vehicle through display isnot limited to an arrow mark. Any direction indicating sign is displayedon the screen from which the direction can be seen is sufficient. Forexample, it may be a figure of a pattern of a steering wheel, whichindicates an arrow with a rotational direction, a figure of a vehiclethat tilts in the direction according to the course, or the like. Ofcourse, the direction indicating sign may be a moving picture as well asa still picture. The direction indicating sign may flicker.

[0378] The above embodiments are premised on that the vehicle approachesa load handling target from the front. However, the steering angle maybe considered at the time of giving an instruction so that a pull-overinstruction is carried out correctly even in the process in which, forexample, the vehicle enters a load handling symmetry from the obliquedirection or approaches the load handling target from the obliquedirection to be pulled over. That is, the steering angle (tire angle) ofthe drive and steering wheel may be detected by a steering angle sensor(tire angle sensor), the state angle of the vehicle with respect to theload handling target (mark) may be calculated from the detected steeringangle, the direction to steering the steering wheel may be acquired fromthe relationship between a change in steering angle and a change in thedistance Yc between the moving target point and mark, and the directionand angle to steer may be displayed on the screen or indicated in voice.

[0379] In an industrial vehicle that does not employ automatic forkpositioning control and is constructed to only display the image of aload carrying work area on the screen of a display device provided in adriver's cab to aid a load handling operation performed by a driver, astructure which notifies only the direction to manipulate the steeringwheel or the operation lever for the driver to position the forks can beemployed. The notification in this case is done by an instructionthrough display on the screen or a voice or sound instruction.

[0380] Although notification to guide a position correction is made onlywhen the vehicle is deviated with respect to a load handling target inthe eighth embodiment, notification may also be made when the positionof the vehicle coincides with the load handling target.

[0381] Eleventh Embodiment

[0382] The present embodiment relates to an industrial vehicle equippedwith a voice notification apparatus capable of notifying a change in thedisplay state of a display device in voice. This embodiment will bedescribed mainly on differences from the individual embodimentsaccording to FIGS. 40 to 45.

[0383]FIG. 40 is a perspective view of a multi lever according to thepresent embodiment. FIG. 41 is a side view of the multi lever. The multilever 31 as a load handling lever is provided on the instrument panel.The multi lever 31 has plural types of operation sections that canensure all the operations of the driving operation and load handlingoperation. As its specific structure is the same as that of the multilever of the first embodiment, the detailed description will be omitted.

[0384]FIG. 42 shows the control circuit of a forklift of the presentembodiment. Formed on a handle knob 17 of the vehicle shown in FIG. 1are a load pickup mode switch 153 and a load deposition mode switch 154,which set the operation mode manually. Those two switches 153 and 154are connected to the input side of the load handling control section 47shown in FIG. 42. When the load pickup mode switch 153 in those switches153 and 154 is depressed, the operation mode is set to the “load pickupmode” and when the load deposition mode switch 154 is depressed, theoperation mode is set to the “load deposition mode”.

[0385] The camera 24 is connected to the input side of the image controlsection 46 and an output device 155 is connected to the output side. Theoutput device 155 has the display screen 28A of the display device 28and the speaker 51, and the image control section 46 displays the image(video image), picked up by the camera 24, on the display screen 28A andcauses the speaker 51 to generate a predetermined sound. To acquire theamount of deviation of the forks 2 at the time of the automatic forkposition control, the image control section 46 executes image processingbased on image data acquired from the camera 24.

[0386] The image control section 46 has the display processing section75, the image processing section 76, the drawing display section 77, thedrawing data memory section 78 and the voice synthesizing section 79.The display processing section 75 outputs a video signal, input from thecamera 24, to the display device 28 in such a way that the image pickedup by the camera 24 is displayed on the screen. The image processingsection 76 receives the image data from the display processing section75, performs an image recognition process based on the image data andcalculates the coordinates of the marks M1 and M2 and the coordinates ofa shift target point 87 or the like on the display screen 28A of thedisplay device 28.

[0387] Based on the results of the processing of the image processingsection 76, the drawing display section 77 displays the drawing of theshift target point 87 and a target line 167 (see FIGS. 43(a), (b)) orthe like on the display screen 28A as drawing data stored in the drawingdata memory section 78. The drawing display section 77 respectivelydisplays, on the display screen 28A, the “load pickup mode” when theoperation mode is the load pickup mode and the “load deposition mode”when the operation mode is the load deposition mode.

[0388] The image processing section 76 has the image recognitionprocessing section 81, the template memory section 82, the imagecomputing section 83 and the display position determining section 84.The load handling control section 47 has the real coordinate positioncalculating section 85 and the deviation amount computing section 86.

[0389] The following will describe the contents of the processesperformed by the image control section 46 and the load handling controlsection 47 at the time of the automatic fork position control accordingto the drawings.

[0390] As automatic fork positioning control is executed, the displayscreen 28A changes to a state after positioning shown in FIG. 43(b) froma state before positioning shown in FIG. 43(a) in case of the loadpickup mode. While both diagrams show the case of a load pickup work topick up a pallet 41 placed in the rack 40, a load deposition work iscarried out in similar procedures. The target line 167 with anapproximately cross shape is drawn on that of the marks M1, M2 displayedon the display screen 28A which is set as a target for positioning ofthe forks 2 at the time of automatic fork positioning control. In caseof the load pickup mode shown in FIG. 43, the mark M1 is highlighted bythe target line 167.

[0391] As the automatic fork positioning control is started bydepressing the activation switch 38 of the multi lever 31, the automaticfork positioning control is executed based on an image picked up bycamera 24. That is, the forks 2 are automatically shifted in up and downand left and right directions, targeting the mark M1 highlighted by thetarget line 167 on the display screen 28A, in such a way that the markM1 coincides with the moving target point mark 87. When the movingtarget point mark 87 coincides with the mark M1 after the shiftoperation, the forks 2 are placed in the adequate position. In a loaddeposition work, the mark M2 coincides with the moving target point mark87.

[0392] The display position determining section 84 for the moving targetpoint mark 87 calculates the center coordinates (It, Jt) of the movingtarget point 87. Its calculation method has been described earlier.

[0393] When the display state of the display screen 28A changes, thevoice synthesizing section 79 shown in FIG. 42 causes the speaker 51 tomake notification according to the change. When the camera 24 is movedfrom a state shown in FIG. 44 or a state where the mark M1 is notdisplayed on the display screen 28A, the state becomes as shown in FIG.43(a) where the mark M1 is displayed on the display screen 28A. Then,when the image recognition processing section 76 identifies the mark M1in case where the work mode is the load pickup mode, the voicesynthesizing section 79 generates a first sound SA from the speaker 51.As the first sound SA, a sound effect, for example,“pippipipopoppopipopoppo . . . ”, is generated.

[0394] Suppose that as the automatic fork positioning control has beenexecuted, the forks 2 have been moved to the suitable position, bringingthe state shown in FIG. 43(b) where the mark M1 coincides with themoving target point mark 87. That is, when the coordinates (I, J) of themark M1 calculated by the image computing section 83 coincide with thecenter coordinates (It, Jt) of the moving target point 87 calculated bythe display position determining section 84, the voice synthesizingsection 79 generates a second sound SB from the speaker 51. As thesecond sound SB, a sound effect, for example, “pippipipopopopipopopo . .. ”, is generated.

[0395] Suppose that as the positioned state of the forks 2 is shifted,the state where the mark M1 coincides with the moving target point mark87 becomes the state shown in FIG. 43(a) where the moving target pointmark 87 comes off the mark M1 coincides. That is, when the coordinates(I, J) of the mark M1 are shifted from the center coordinates (It, Jt)of the moving target point 87 calculated by the display positiondetermining section 84, the voice synthesizing section 79 generates athird sound SC from the speaker 51. As the third sound SC, a soundeffect, for example, “pippi”, is generated.

[0396] When the load handling target comes away from the camera 24 andthe mark M1 comes off the image pickup range of the camera 24, the stateshown in FIG. 43(a), (b), where the mark M1 is displayed on the displayscreen 28A, becomes the state shown in FIG. 44, where the mark M1 comesoff the display screen 28A. That is, when the image recognitionprocessing section 81 does not identify the mark M1, the voicesynthesizing section 79 generates a fourth sound SD from the speaker 51.As the fourth sound SD, a sound effect, for example, “poppoppo”, isgenerated. The generation of those sounds SA to SD is similarly done inload deposition mode, too.

[0397]FIG. 45 shows the relationship between a change in the state ofmark identification and the first sound SA to the fourth sound SD. Asshown in the diagram, when the state where the mark M1, M2 could not beidentified is shifted to the state where the mark M1, M2, identifiedthough it is, does not coincide with the moving target point mark 87,the first sound SA is generated, and when the change occurs in theopposite direction, the fourth sound SD is generated.

[0398] When the state where the mark M1, M2, identified though it is,does not coincide with the moving target point mark 87 is shifted to thestate where the mark M1, M2 is identified and coincides with the movingtarget point mark 87, the second sound SB is generated, and when thechange occurs in the opposite direction, the third sound SC isgenerated.

[0399] When the state where the mark M1, M2 could not be identified isshifted to the state where the mark M1, M2 is identified and coincideswith the moving target point mark 87, the second sound SB is generated,and when the change occurs in the opposite direction, the fourth soundSD is generated.

[0400] The above allows the driver to check if the camera 24 catches themark M1, M2 and the image of the mark M1, M2 is identified and if theautomatic fork positioning control is completed without watching thedisplay screen 28A. Therefore, the driver need not see the displayscreen 28A and can give attention to other works by that amount so thatthe workability at the time of a load carrying work is improved.

[0401] The controller 45 shown in FIG. 42 has a remaining battery powercalculating section 175 as measuring means. The remaining battery powercalculating section 175 calculates the remaining power of a battery 7installed on the vehicle body 3 and determines whether or not theremaining power is equal to or lower than a threshold value. Then, basedon the decision result from the remaining battery power calculatingsection 175, the voice synthesizing section 79 generates a fifth soundSE when the remaining power of the battery 7 is equal to or lower thanthe threshold value (e.g., 10% of the total capacity). As the sound SE,for example, a message “Please charge the battery” is generated.

[0402] When the vehicle is keyed on and the automatic fork positioningcontrol system is activated, the voice synthesizing section 79 generatesa sixth sound SF from the speaker 51. The sixth sound SF is generated,for example, after the program in the controller 45 is activated andbefore the main loop of the image recognition process starts. As thesound SF, for example, a message “Accessing computer” is generated.

[0403] Therefore, this embodiment has the following advantages.

[0404] The sounds SA to SD are generated from the speaker 51 inaccordance with the presence/absence of the mark M1 (M2) on the displayscreen 28A and the positional relationship between the mark M1 (M2) andthe moving target point 87. Therefore, the driver can check if thecamera 24 catches the mark M1, M2 and the image of the mark M1, M2 isidentified and if the automatic fork positioning control is completedwithout watching the display screen 28A. Thus, the driver need not seethe display screen 28A and can give attention to other works by thatamount so that the workability at the time of a load carrying work isimproved.

[0405] As a sound is generated from the speaker 51 when the remainingpower of the battery 7 becomes equal to or lower than the thresholdvalue, the driver (worker) can see through the sound that the remainingpower of the battery 7 is not much.

[0406] Because the sound SF is generated from the speaker 51 when theautomatic fork positioning control system is activated, it is possibleto check through the sound whether or not the system has been activatednormally.

[0407] The embodiment is not limited to the eleventh embodiment, but maybe modified in the following forms.

[0408] The first to sixth sounds SA to SF are not limited to theaforementioned sound effects and messages. That is, the sound effects ofthe individual sounds in use may be other than the aforementioned ones,and messages may be generated instead of the sound effects. With regardto the messages of the sounds SE and SF, other than the above-describedcontents may be used and sound effects may be generated in place of themessages.

[0409] Not all the sounds SA to SD are limited to the generation type,and the structure may be such that at least one of them is generated. Atthis time, as what is desired most by the driver is the state ofcoincidence of the mark M1 (M2) and the moving target point mark 87 witheach other, it is preferable that of those four sounds SA-SD, the secondand third sounds SB and SC be generated.

[0410] The threshold value at the time of generating the remainingbattery power is not limited to 10% of the entire battery capacity, butthe value may be set freely. The sound SE should not necessarily begenerated when the remaining battery power becomes low, and a process ofgenerating the sound SE may be omitted.

[0411] The sound SF should not necessarily be generated when theautomatic fork positioning control system is activated, and a process ofgenerating the sound SF may be eliminated. The timing to activate thesystem is not limited to the key-on timing, but, for example, anexclusive activation switch for the system may be provided so that whenthe switch is set on, the system is activated.

[0412] The speaker 51 should not necessarily be incorporated in theoutput device 155 but may be installed on the vehicle body 3.

[0413] The display means is not limited to the display device 28 thatshows an image from the camera 24. For example, a lamp is provided thatis lit when the mark M1 (M2) is outside the image pickup range of thecamera 24; another lamp is provided that is lit when the position of themark M1 (M2), lying inside the image pickup range of the camera 24though, does not coincide with the position of the forks 2; and anotherlamp is provided that is lit when the mark M1 (M2) is positioned withthe forks 2. The structure may be such that when the lighting states ofthose lamps change, sounds according to the stage changes are generated.

[0414] When the mark M1 (M2) on the display screen 28A is shifted fromthe moving target point mark 87, for example, the display color may bechanged, such as the entire screen of the display screen 28A beingdisplayed in red. The process of changing the display color may becarried out under individual conditions, such as when the mark M1 (M2)coincides with the moving target point mark 87, when the mark M1 (M2) isdisplayed on the display screen 28A and when the mark M1 (M2) comes offthe display screen 28A.

[0415] The automatic fork positioning control system should notnecessarily have a function of automatically positioning the forks 2.That is, the structure may be such that only the presence/absence of themark M1 (M2) on the display screen 28A or the positional relationshipbetween the mark M1 (M2) and the moving target point mark 87 is acquiredby performing an image recognition process of the mark M1 (M2).

[0416] The drive amounts of the individual cylinders may be calculated,and the position of the forks 2 may be acquired based on the amounts tocalculate the moving target point mark 87. The moving target point mark87 should not necessarily be displayed on the display screen 28A.

[0417] A target for sound notification is not limited to the automaticfork positioning control system. For example, a lamp is provided, whichis lit when the tilt angle becomes horizontal, and the lamp is lit asthe forks 2 with a load placed thereon are leveled at the time of awork. At this time, there may be a case where the forks 2 take aslightly forward tilted state if the forks 2 are lifted up fast.Furthermore, a message “Please lower the ascending speed” may begenerated from the speaker 51 when the tilt angle is changed.

[0418] Twelfth Embodiment

[0419] The twelfth embodiment of the invention will be described mainlyon differences from the first embodiment according to FIGS. 46 to 52.This embodiment relates to an apparatus, which displays work images atthe time of a load pickup work and load deposition work and at the timethe vehicle is running.

[0420] An apparatus shown in, for example, FIG. 59 is known as aconventional apparatus of this type. The apparatus has a first camera201 for monitoring forward, which is provided on the upper portion of amast 200, a second camera 203 for monitoring the distal end portions offorks, which is provided on the lower portion of a finger bar 202, and athird camera 104 for front monitoring, which is provided on theintermediate portion of the mast 200. The images that are picked up bythe cameras 201, 203 and 204 are selectively displayed on a monitor as adriver (operator) operates a camera select switch of an image monitorunit 205.

[0421] At the time of load pickup, for example, selecting the secondcamera 203 allows forks 206 to be easily inserted into a pallet at aposition higher than the driver's seat while viewing the up, down, leftand right states of the forks 206 is displayed on the monitor of theimage monitor unit 205.

[0422] At the time a load deposition work or load pickup work is carriedout with respect to a pallet on a tall truck, selecting the third camera204 can allow a load deposition work or load pickup work with respect toa pallet blocked by a load on the forks 206 or a back rest 207 to becarried out easily while viewing a state near the pallet displayed onthe monitor.

[0423] Further, at the time of driving, selecting the first camera 201can allow the vehicle blocked by a load on the forks 206 to be driveneasily while viewing an image in front of the vehicle displayed on themonitor.

[0424] However, the apparatus requires that the driver should switch theimage displayed on the monitor to an image in front of the vehicle froman image of the distal ends of the forks displayed on the monitor byperforming the switching operation of the camera select switch.Likewise, for deposition of a load on a truck after running is stopped,the driver should perform the switching operation of the camera selectswitch again to switch the image to be displayed to an image in front ofthe middle portion from an image in front of the vehicle.

[0425] It is therefore necessary for the driver to perform the switchingoperation of the camera select switch to switch the display image on themonitor every time a work state is changed, and there is some room forimprovement of the work efficiency.

[0426] By way of contrast, for each of a plurality of different works,the present embodiment can provide a driver with a work image forsupporting the work view field of the driver who does that work, and,what is more, does not need a switching operation for a work image to bedisplayed at the time of changing the work.

[0427] In the present embodiment, as shown in FIGS. 46 and 47, first, asthe protraction operation of the lift cylinder 15A is performed at astate where the forks 2 are at the lowest lift-down position, the mast13 lifts up the forks 2 from the lowest lift-down position to a firstheight position (reference height position) near the top end of theouter mast 13A. That is, at this time, the middle mast 13B and the innermast 13C are left unlifted with respect to the outer mast 13A. As theprotraction operation of the lift cylinders 15B is further done fromthat state to lift the middle mast 13B and the inner mast 13C withrespect to the outer mast 13A, the forks 2 are lifted up from the upperend position of the outer mast 13A to a second height position, which isthe highest.

[0428] A cross beam 13D of the outer mast 13A is provided with theheight sensor 58 for detecting a state where the inner mast 13C islifted up from the lowest lift-down position or a high elevation statewhere the forks 2 are lifted up beyond the first height position. Thelift cylinders 15B is provided with the load weight sensor 59 fordetecting the weight of the load on the forks 2.

[0429] As shown in FIGS. 46 and 47, a drive camera 242 which picks up animage in front of the vehicle for supporting the forward driving of thevehicle is provided on the outer surface of the left-hand side outermast 13A.

[0430] The drive camera 242 is so provided as to be able to pick up, forexample, an image PD in front of the vehicle in a moving passage C orthe like in which storage racks 40 are provided on the left and right,as shown in FIG. 3, from the left-hand side of the load 43 on the forks2 moved down to a position lower than the first height position. Thefrontward image PD in front of the vehicle, which is picked up by thedrive camera 242, can supplement the forward view field of the driverwhich is blocked by the load 43 on the forks 2 and aid the forwardrunning of the vehicle.

[0431] As shown in FIGS. 46 and 47, the camera unit 23 for load handlingwhich picks up an image in front of the forks 2 to aid a load depositionwork and load pickup work is provided on the front side of the sideshifter 16.

[0432] As described above, the load handling camera 24 is placed in the“storage position” which is positioned above the top surfaces of theforks 2 when the entire camera unit 23 is retained in the housing 22.When the lower portion of the camera unit 23 projects below the housing22, the load handling camera 24 is placed in the “lift-down position”which is positioned below the bottom surfaces of the forks 2, as shownin FIG. 46.

[0433] At the time of a “load pickup work”, the load handling camera 24is placed in the “storage position” and picks up an image in front ofthe forks 2 from between the left and right forks 2 without a load 43,as shown in FIG. 49(a), through the image pickup window 22A provided onthe lower front surface of the housing 22. Then, a frontward image PWincluding the front surface of the pallet 41 on which the load to bepicked up is placed is picked up as shown in FIG. 50.

[0434] At the time of a “load deposition work”, on the other hand, theload handling camera 24 is placed in the “lift-down position” and picksup an image in front of the forks 2 directly with the image pickupsection 24A from below the load 43 on the forks 2, as shown in FIG.49(b). Then, the frontward image PW including the front surface of theshelf plate 42 for load deposition in the storage rack 40 is picked upas shown in FIG. 51.

[0435] As shown in FIGS. 46 and 47, the display device 28 is provided onthe bottom surface of the roof 27 located above the driver's seat 9. Thedisplay device 28 is comprised of, for example, a liquid crystal displaydevice. The display device 28 is provided to present the driver in thedriver's seat 9 with one of the image in front of the vehicle that ispicked up by the drive camera 242 and the image in front of the forks 2that is picked up by the load handling camera 24.

[0436] As shown in FIG. 52, the height sensor 58, the load weight sensor59, the tilt angle sensor 60, the activation switch 112 that is operatedat the time of automatically positioning the forks, and thepotentiometers 96 a to 99 a (see FIG. 26) of the individual levers areelectrically connected to the input side of the load handling controlsection 47. The camera lifting motor 61 as an electric actuator iselectrically connected to the output side of the load handling controlsection 47.

[0437] The height sensor 58, the drive camera 242 and the load handlingcamera 24 are electrically connected to the input side of the imagecontrol section 46 and the display device 28 is electrically connectedto the output side thereof.

[0438] The load handling control section 47 holds the load handlingcamera 24 in the “storage position” in a range where the height positionof the forks 2 ranges from the lowest lift-down position to the firstheight position. The load handling control section 47 switches the loadhandling camera 24 to the “storage position” or “lift-down position” inaccordance with the weight of the load 43 on the forks 2 when the heightposition of the forks 2 is beyond the first height position. When theweight of the load 43 is equal to or smaller than a preset decisionvalue, the load handling control section 47 considers that there is noload 43 on the forks 2 and a “load pickup work” is to be done, andplaces the load handling camera 24 in the “storage position”. When theweight of the load 43 exceeds the decision value, on the other hand, itis considered that there is a load 43 on the forks 2 and a “loaddeposition work” is to be done, and the load handling camera 24 is setin the “lift-down position”.

[0439] The reason why the load handling camera 24 is placed in the“storage position” in case of a height equal to or lower than the firstheight position is that when the forks 2 forks are lifted down to thelowest lift-down position, the load handling camera 24 does not collideon the floor. At the time of a “load pickup work” with the forks 2elevated beyond the first height position, it becomes a state of pickingup the image PW in front of the forks 2 from between the left and rightforks 2 as shown in FIG. 49(a). Likewise, at the time of a “loaddeposition work”, it becomes a state of picking up the image PW in frontof the forks 2 from below the load 43 on the forks 2 as shown in FIG.49(b).

[0440] The automatic fork positioning control is executed when theactivation switch 112 is operated in the high elevation state in whichthe forks 2 are lifted up beyond the first height position. As theautomatic fork positioning control, the load handling control section 47automatically positions the forks 2 in the load pickup target positionfor the pallet 41 on which the load 43 is placed at the time of a “loadpickup work” as shown in FIG. 49(a). At the time of a “load depositionwork”, it automatically positions the forks 2 in the load depositiontarget position for the shelf plate 42 on which the load 43 is to beplaced as shown in FIG. 49(b). Please refer to the individualembodiments described previously for the details of this control.

[0441] The image control section 46 switches an image to be displayed onthe display device 28 between the image PD in front of the vehicle,which is picked up by the drive camera 242, and the image PW in front ofthe forks 2, which is picked up by the load handling camera 24, based onthe detection signal from the height sensor 58.

[0442] When the height of the forks 2 is equal to or lower than thefirst height position, the image control section 46 displays the imagePD in front of the vehicle, which is picked up by the drive camera 242,on the display device 28. In the state in which the height of the forks2 is equal to or lower than the first height position, the driver can doload pickup or load deposition relatively easily while directly viewingthe pallet 41 or shelf plate 42, but it is difficult to see in front ofthe vehicle when the vehicle is moved forward because of the load 43 onthe forks 2 blocking the view. When the height of the forks 2 is equalto or lower than the first height position, the image control section 46displays the image PD in front of the vehicle so that the driver candrive the vehicle forward while viewing the image PD in front of thevehicle displayed on the display device 28.

[0443] When the height of the forks 2 exceeds the first height position,on the other hand, the image control section 46 displays the image PW infront of the forks 2, which is picked up by the load handling camera 24,on the display device 28. In the state in which the height of the forks2 exceeds the first height position, it is not easy for the driver to doa load pickup or load deposition work while directly viewing the pallet41 or shelf plate 42, and it is less likely to drive the vehicleforward. Accordingly, at the time of positioning the forks 2 manually,the driver is allowed to be able to position the forks 2 to the pallet41 or the shelf plate 42 while viewing the image PW in front of theforks 2 displayed on the display device 28. At the time of positioningthe forks 2 under automatic fork positioning control, the driver isallowed to be able to roughly position the forks 2 to the pallet 41 orthe shelf plate 42 while viewing the image PW in front of the forks 2displayed on the display device 28.

[0444] When the forks 2 are lifted up beyond the first height positionto pick up the load 43 stored for each pallet 41 on the shelf plate 42located at a high place in the storage rack 40, the image controlsection 46 displays the image PW in front of the forks 2, which ispicked up by the load handling camera 24, on the display device 28. Thiscan allow the driver to see, on the display device 28, the image infront of the pallet 41 for the load 43 stored on the shelf plate 42 at ahigh place at which the height relationship with the forks 2 isdifficult to grasp and which is blocked by the forks 2 or the back restor the like and is difficult to see with eyes. It is possible to easilyposition the forks 2 to the pallet 41 manually while viewing the imagePW in front of the forks 2.

[0445] And, merely causing the mast 13 to perform a reach operationfrontward of the vehicle can allow the forks 2 to be inserted into thepallet 41. Or, the forks 2 can be roughly positioned to the pallet 41while viewing the image PW in front of the forks 2 which is displayed onthe display device 28. Then, the forks 2 can be position accurately tothe pallet 41 by automatic control.

[0446] Likewise, even when the load 43 is placed together with thepallet 41 on the shelf plate 42 at a high place in the storage rack 40,the image control section 46 displays the image PW in front of the forks2 on the display device 28. Therefore, the driver can easily position,or roughly position, the forks 2 while viewing the image PW in front ofthe forks 2 which is to be displayed on the display device 28. And,merely causing the mast 13 to perform a reach operation frontward of thevehicle can allow the load 43 to be carried over the shelf plate 42 forload deposition.

[0447] When the forks 2 are lifted down below the first height positionto drive the vehicle forward after load pickup, on the other hand, theimage control section 46 displays the image PD in front of the vehicle,which is picked up by the drive camera 242, on the display device 28 inplace of the image PW in front of the forks, which is picked up by theload handling camera 24. Therefore, the driver can drive easily thevehicle forward while viewing the image PD in front of the vehicle,which is blocked by the load 43 on the forks 2 and hard to see.

[0448] The present embodiment discussed in detail above has thefollowing advantages.

[0449] The drive camera 242 picks up the image PD in front of thevehicle with respect to forward driving of the vehicle that is done withthe forks 2 lifted down, and the load handling camera 24 picks up a workimage for a load carrying work which is carried out with the forks 2lifted high. The image control section 46 determines whether or not awork to be done then is a load carrying work or forward driving from theheight position of the forks 2, and displays the image PD in front ofthe vehicle or the image PW in front of the forks 2 on the displaydevice 28 according to the work.

[0450] Therefore, the driver is presented with a work image picked up byeach of the drive camera 242 and the load handling camera 24 accordingto the work at that time. As a result, a switching operation for a workimage to be displayed is not necessary at the time of switching a loadcarrying work and a moving work, thus ensuring a further improvement onthe work efficiency.

[0451] An image in front of the vehicle, which supplements the field ofview of the driver when the vehicle is driven forward is picked up bythe drive camera 242 provided on the outer mast 13A from the left-handside of the load 43. This can allow the vehicle to run forward easilywhile viewing, on the display device 28, the image in front of thevehicle, which is blocked by the load on the forks 2 and is difficult todirectly see with one's eyes.

[0452] The load handling camera 24 provided in front of the carriage 14,which is lifted up and down together with the forks 2, picks up an imagein front of the forks 2 which supplements the field of view of thedriver at the time of a “load pickup work” or “load deposition work”. Itis therefore possible to easily position the forks 2 while viewing, onthe display device 28, the front image of the pallet 41 or the shelfplate 42 which is blocked by the load 43 on the forks 2 and is difficultto directly see with eyes.

[0453] When the inner mast 13C is positioned in or below the lowestlift-down position or the first height position, it is determined thatthe vehicle is in a state to run based on the height of the forks 2 thatis detected by the height sensor 58; and when the inner mast 13C ispositioned above the first height position, it is determined that a loadcarrying work is to be done. It is therefore possible to discriminate,with a simple structure, between the state where the vehicle is drivenforward with the forks 2 set at a low height and the state for doing aload carrying work with the forks 2 lifted high.

[0454] The load handling control section 47 acquires a positionaldeviation amount of the forks 2 with respect to the pallet 41 or theshelf plate 42 from the image PW in front of the forks 2, which ispicked up by the load handling camera 24, and controls the lift cylinder15A, 15B and the side shift cylinder 71 to control the forks 2 to theload pickup target position or load deposition target position. It isthus possible to do easily a load pickup work or load deposition workeven when the forks 2 are lifted high.

[0455] Thirteenth Embodiment

[0456] The thirteenth embodiment of the present invention will bedescribed according to FIGS. 53 to 56. The present embodiment differsfrom the twelfth embodiment only in that the height sensor 58, the drivecamera 242, the load handling camera unit 23 and the image controlsection 46 of the twelfth embodiment are changed to a height switch 270,a work camera unit 272 and a display control unit 277. Therefore, samereference symbols are given to those constituents, which are the same asthose of the twelfth embodiment, and their descriptions will be omitted.

[0457] As shown in FIG. 53, the cross beam 13D of the outer masts 13A isprovided with the height switch 270 for discriminating whether or notthe inner masts 13C is lifted from the lift-down position, i.e., whetheror not the height position of the forks 2 is equal to or lower than thefirst height position.

[0458] A cross beam 271 which links the left and right inner masts 13Cis provided with the work camera unit 272 which picks up an image infront of the vehicle for supporting the forward drive of the vehicle andan image in front of the forks 2 for supporting load pickup and loaddeposition works. The work camera unit 272 is provided on the bottomsurface of the cross beam 271 to the right so that it does not interferewith a piston rod 15Aa (shown in FIG. 54) of the lift cylinder 15A.

[0459] As shown in FIG. 54, the work camera unit 272 comprises a pair ofsupport members 273, a casing 274, a work camera 275 and a motor unit276. Both support members 273 are fixed to the cross beam 271. Thecasing 274 is supported on both support members 273 in such a way as tobe tiltable about the axial line extending in the left and rightdirection of the vehicle. The work camera 275 is accommodated in thecasing 274.

[0460] The work camera 275 picks up an image in front of the vehiclefrom a pickup window 274 a provided in the casing 274. The work camera275 is electrically connected to the display control unit 277 providedinside the vehicle body 3.

[0461] The motor unit 276 can be switched between a “drive mode” inwhich the work camera 275 is tilted to direct the image pickup directiondown frontward of the vehicle and a “load handling mode” in which it isdirected frontward of the vehicle approximately horizontally, as shownin FIGS. 54 and 55. The motor unit 276 is electrically connected to thedisplay control unit 277.

[0462] In “drive mode”, the work camera 275 can pick up an image infront of the vehicle from above the load 43 on the forks 2 lifted downnear the reach legs 4. That is, as the work camera 275 in the presentembodiment is positioned more frontward of the vehicle than the positionof the driver, it picks up a frontward image including the area in frontof the vehicle which is blocked by the load 43 on the forks 2 and ishard for the driver to see with eyes.

[0463] As the mast 13 is a full free type, the work camera 275 picks upan image in front of the forks 2 from below the forks 2 in “loadhandling mode”, regardless of the height of the forks 2 lifted higherthan the first height position. That is, when the height of the forks 2exceeds the first height position and the inner masts 13C is lifted withrespect to the outer masts 13A, the work camera unit 272 is lifted upand down together with the forks 2 while keeping the positionalrelationship with the forks 2 at the first height position. Thepositional relationship at the first height position is the positionwhere a frontward image can be picked up from below the forks 2 as shownin FIGS. 54 and 55, and is equivalent to the “lift-down position” in thetwelfth embodiment.

[0464] In the present embodiment, the height switch 270, the supportmembers 273, the casing 274, the motor unit 276 and the display controlunit 277 constitute the image pickup direction switching means. Thedisplay control unit 277 and the display device 28 constitute the imagedisplay means. Further, the support members 273, the casing 274, themotor unit 276 and the display control unit 277 constitute the stateadjusting means, the height switch 270 and the display control unit 277constitute the work discrimination means and height detection means, andthe display control unit 277 constitutes the switching control means.Further, the lift cylinders 15, the display control unit 277, the loadhandling control section 47, the side shift cylinder 71, the oil controlvalve 64, the electromagnetic changeover valves 66 and 69 and the workcamera 275 constitute the position control means.

[0465] As shown in FIG. 56, the height switch 270 and the work camera275 are electrically connected to the input side of the display controlunit 277, and the display device 28 and the motor unit 276 areelectrically connected to the output side thereof. Based on a detectionsignal from the height switch 270, the display control unit 277 controlsthe motor unit 276 to switch the image pickup direction of the workcamera 275 between the “drive mode” and the “load handling mode”.

[0466] When the height of the forks 2 is equal to or lower than thefirst height position, the display control unit 277 sets the work cameraunit 272 in the “drive mode” and displays an image in front of thevehicle, which is picked up by the work camera 275, on the displaydevice 28 in this state. That is, when the height of the forks 2 isequal to or lower than the first height position, the display controlunit 277 displays an image in front of the vehicle on the display device28 so that the driver can drive the vehicle forward while viewing theimage in front of the vehicle displayed on the display device 28.

[0467] When the height of the forks 2 exceeds the first height position,the display control unit 277 sets the work camera unit 272 in the “loadhandling mode” and displays an image in front of the forks 2, which ispicked up by the work camera 275, on the display device 28 in thisstate.

[0468] When the forks 2 are lifted above the first height position atthe time of a “load deposition work” and are positioned in the vicinityof the load deposition target position with respect to the shelf plate42, the work camera unit 272 in “load handling mode” picks up an imagein front of the forks 2 including the mark M2 on the shelf plate 42 frombelow the load 43. Likewise, when the forks 2 are positioned in thevicinity of the load pickup target position with respect to the pallet41 placed on the shelf plate 42 at the time of a “load pickup work”, animage in front of the forks 2 including the mark M2 on the shelf plate42 is picked up.

[0469] When the height of the forks 2 exceeds the first height position,the display control unit 277 displays an image in front of the forks 2on the display device 28 so that the driver can position the forks 2 tothe pallet 41 or the shelf plate 42 while viewing the image PW in frontof the forks 2 displayed on the display device 28.

[0470] In this embodiment, as in the twelfth embodiment, the displaycontrol unit 77 identifies the image of the mark M1, M2 shown on thefront side of the pallet 41 or the shelf plate 42 and performs automaticfork positioning control to automatically position the forks 2 in theload pickup target position or the load deposition target position. Inthis embodiment, however, the work camera 275 is provided on the innermasts 13C and is not moved leftward and rightward together with theforks 2, so that the relative positional relationship between the forks2 and the work camera 275 in the left and right direction (Y direction)changes. In this respect, a side stroke sensor 278 (see FIG. 11) whichdetects the side shift amount of the forks 2 is provided and automaticfork positioning control based on the detected value is executed.

[0471] In the present embodiment, when the forks 2 are lifted above thefirst height position to pick up the load 43 stored at a high place inthe storage rack 40, the display control unit 277 sets the image pickupdirection of the work camera 275 to the “load handling mode” and thework camera 275 displays an image in front of the forks 2 on the displaydevice 28.

[0472] Therefore, the driver can see, on the display device 28, theimage in front of the forks 2 including the front side of the pallet 41for the load 43 to be stored at a high place at which the heightrelationship with the forks 2 is difficult to grasp and which is hard tosee with eyes. And it is possible to easily position the forks 2 in theload pickup position by a manual operation.

[0473] Likewise, at the time the load 43 at a high place in the storagerack 40 is loaded together with the pallet 41, the work camera 275 isalso set in the “load handling mode” and an image in front of the forks2 is displayed on the display device 28. With respect to a high place,which is difficult to see with one's eyes, therefore, the driver caneasily position the forks 2 while viewing the image in front of theforks 2 displayed on the display device 28.

[0474] When the forks 2 are lifted down below the first height positionto drive the vehicle forward after load pickup, the display control unit77 switches the image pickup direction of the work camera 275 to the“drive mode” from the “load handling mode”. Then, an image in front ofthe vehicle including an area directly in front is displayed on thedisplay device 28. Therefore, the driver can easily drive the vehicleforward while viewing, on the display device 28, the image in front ofthe vehicle including the image directly in front which is blocked bythe load 43 on the forks 2 and is hard to see with eyes.

[0475] The present embodiment discussed in detail above has thefollowing advantages.

[0476] An image in front of the vehicle and an image in front of theforks 2 can be picked up by switching the image pickup direction of thesingle work camera 275. Further, the display control unit 277discriminates a work at that time based on the height position of theforks 2 and switches the image pickup direction of the work camera 275according to the discriminated work.

[0477] As the image pickup direction of the single work camera 275 isswitched, therefore, a work image, which supports a work at that time isautomatically switched and displayed. As a result, at the time the workis changed, it is unnecessary to switch the work image to be displayed,thus ensuring a further improvement of the work efficiency.

[0478] The work camera 275 is provided on the cross beam 13D of theinner masts 13C of the full free type mast 13. The height of the forks 2is detected by the height switch 270 and when the forks 2 are positionedin or lower than the first height position, the image pickup directionis set to the direction to pick up an image in front of the vehicle, andwhen it exceeds the first height position, the image pickup direction isset to the direction to pick up an image in front of the forks 2.

[0479] At a low height where the inner masts 13C is not lifted up fromthe lift-down position and only the forks 2 are lifted up and down,therefore, an image in front of the vehicle can be picked up from theheight of the same viewpoint for the vehicle body 3. At a high heightwhere the inner masts 13C is lifted up and down together with the forks2, an image in front of the forks 2 can be picked up with apredetermined positional relationship with the forks 2. Unlike in thetwelfth embodiment, therefore, it is unnecessary to provide the drivecamera separately from the load handling camera.

[0480] Fourteenth Embodiment

[0481] The fourteenth embodiment of the present invention as embodiedinto a work view field aiding apparatus for a counterbalance typeforklift truck will be described according to FIGS. 57 and 58.

[0482] As shown in FIG. 57, in a counterbalance type forklift(hereinafter simply called forklift) 280, a driver's seat 282 isprovided on the front portion of a vehicle body 281 and a mast 283 isprovided on the front side of the driver's seat 282. Drive wheels 284are provided on the front portion of the vehicle body 281 and steeredtire wheels 285 are likewise provided on the rear portion.

[0483] The mast 283 is supported on the front axle in such a way as tobe tiltable in the forward and backward direction with respect to thevehicle body 281 and is tilted by the protraction and retraction actionof a tilt cylinder 286. The mast 283 is a two-level slide mast and hasouter masts 287 supported on the vehicle body 281 in a tiltable mannerand inner masts 288 supported on the outer masts 287 in a liftablemanner. By causing the inner masts 288 to perform a lift-up/down actionby the protraction and retraction actions of the unillustrated liftcylinders fixed to the outer masts 287, a lift bracket 289 and forks290, which are supported on the inner masts 288 in a liftable manner,are lifted up and down.

[0484] A shift lever 291 for changing the forward and backward movementsof the vehicle is provided on the driver's seat 282. The change positionof the shift lever 291, i.e., the forward moving state or the backwardmoving state, is detected by a shift switch 292. The shift switch 292 iselectrically connected to a display control unit 293 provided inside thevehicle body 281.

[0485] A forward movement camera 294 for picking up an image in front ofthe vehicle, which supports the forward driving of the vehicle, isprovided on the outer surface of the left-hand side outer mast 287. Theforward movement camera 294 is electrically connected to the displaycontrol unit 293.

[0486] The forward movement camera 294 picks up an image in front of thevehicle including a forward area of the vehicle from the left-hand sideof the load 43 on the forks 290 that blocks the forward view field ofthe driver. The image in front of the vehicle, which is picked up by theforward movement camera 294, can supplement the forward view field ofthe driver, which is blocked by a load on the forks 290 at the time ofdriving the vehicle forward, and can support the forward driving of thevehicle.

[0487] A backward movement camera 295 for picking up an image at theback of the vehicle, which supports the backward driving of the vehicle,is provided on the outer surface of the rear portion of the vehicle body281. The backward movement camera 295 is electrically connected to thedisplay control unit 293.

[0488] The backward movement camera 295 picks up an image at the back ofthe vehicle including a rearward area of the vehicle, which is hard tosee with eyes. The image at the back of the vehicle, which is picked upby the backward movement camera 295, can supplement the backward viewfield of the driver, which is blocked by the rear portion of the vehiclebody 281 at the time of driving the vehicle backward, and can supportthe backward driving of the vehicle, without making the driver take anuncomfortable pose.

[0489] A display device 297 is provided on the bottom surface of a roof296 above the driver's seat 282. The display device 297 is electricallyconnected to the display control unit 293 and presents the driver at thedriver's seat 282 with an image in front of the vehicle, which is pickedup by the forward movement camera 294, or an image at the back of thevehicle, which is picked up by the backward movement camera 295.

[0490] A back rest 298 of the forklift 280 is provided with the loadhandling camera unit 23 equipped with a load handling camera similar tothe one in the twelfth embodiment. A height switch 299 for detecting ifthe height of the forks 290 is equal to or lower than a preset referenceheight position is provided on the outer masts 287. The reference heightposition is equivalent to the first height position in the twelfthembodiment.

[0491] In this embodiment, the display control unit 293 and the displaydevice 297 constitute the work image display means, and the heightswitch 299 and the display control unit 293 constitute the displaycontrol means and work discrimination means. The display control unit293 is the display switching means, and the height switch 299 is theheight detection means. The load handling camera 24, the forwardmovement camera 294 and the backward movement camera 295 are workcameras, and the forward movement camera 294 and the backward movementcamera 295 are drive cameras.

[0492] As shown in FIG. 58, the load handling camera 24, the shiftswitch 292, the forward movement camera 294, the backward movementcamera 295 and the height switch 299 are electrically connected to theinput side of the display control unit 293, and the display device 297is electrically connected to the output side thereof. The height switch299 is electrically connected to the input side of the load handlingcontrol section 47.

[0493] When the height position of the forks 290 exceeds the referenceheight position based on a detection signal from the height switch 299,the display control unit 293 displays an image in front of the forks290, which is picked up by the load handling camera 24, on the displaydevice 297.

[0494] When the height position of the forks 290 is equal to or lowerthan the reference height position, the display control unit 293displays an image in front of the vehicle, which is picked up by theforward movement camera 294, on the display device 297 when the shiftlever 291 is in the forward drive position based on the switched stateof the shift switch 292. When the shift lever 291 is in the backwarddrive position, an image at the back of the vehicle, which is picked upby the backward movement camera 295, is displayed on the display device297.

[0495] In this embodiment, the display control unit 293 also identifiesthe image of the mark M1, M2 shown on the front side of the pallet 41 orthe shelf plate 42 and acquires the barycentric coordinates and distanceinformation of each mark M1, M2. Then, based on the barycentriccoordinates and distance information acquired from the display controlunit 293, the load handling control section 47 controls theunillustrated lift cylinders and side shift cylinder to performautomatic fork positioning control to automatically position the forks290 in the load pickup target position or the load deposition targetposition.

[0496] When the forks 290 are lifted high above the reference heightposition, the image in front of the forks 290, which is picked up by theload handling camera 24, is displayed on the display device 297.Therefore, the driver can see, on the display device 297, the image infront of the forks 290 including the front side of the pallet 41 for theshelf plate 42 which is blocked by the load 43 on the forks 290 or theback rest 298 or the like and is hard to directly see with eyes. Then,it is possible to position the forks 290 easily in the load pickuptarget position or the load deposition target position by a manualoperation or under automatic control.

[0497] When the shift lever 291 is switched to the forward driveposition with the forks 290 lifted down to or below the reference heightposition, the image in front of the vehicle, which is picked up by theforward movement camera 294, is displayed on the display device 297.Therefore, the driver can easily drive the vehicle forward whileviewing, on the display device 297, the image in front of the vehicleincluding the frontward area of the vehicle, which is blocked by theload 43 on the forks 290 and is hard to see directly with one's eyes.

[0498] When the shift lever 291 is likewise switched to the backwarddrive position at or below the reference height position, the image atthe back of the vehicle, which is picked up by the backward movementcamera 295, is displayed on the display device 297. Therefore, thedriver can easily drive the vehicle backward while viewing, on thedisplay device 297, the image at the back of the vehicle, which isblocked by the rear portion of the vehicle body and is hard to seedirectly with one's eyes, without taking an uncomfortable pose.

[0499] The present embodiment discussed in detail above has thefollowing advantages.

[0500] The forward movement camera 294, which picks up an image in frontof the vehicle, and the backward movement camera 295, which picks up animage at the back of the vehicle, are provided in addition to the loadhandling camera 24. The image in front of the vehicle is displayed atthe time the vehicle is running forward, and the image at the back ofthe vehicle is displayed at the time the vehicle is running backward. Itis therefore possible to carry out a load carrying work easily, theforward driving of the vehicle and the backward driving of the vehicle.

[0501] The drive camera 242 in the twelfth embodiment may be provided onthe cross beam 271, not on the inner masts 13C, so that an image infront of the vehicle is picked up from above the load 43 on the forks 2at the time of forward driving. Even this structure can provide the sameadvantages as those of the twelfth embodiment.

[0502] In the twelfth embodiment, a small load handling camera may beprovided in a recess opening to the front face of the distal end portionof the forks instead of the load handling camera unit 23 to pick up animage in front of the forks 2 with a constant positional relation shipwith the forks 2. Even this structure can provide the same advantages asthose of the twelfth embodiment.

[0503] In the fourteenth embodiment, the forward movement camera 294 maybe provided on the roof 296, not the outer masts 287. Even such astructure can provide the same advantages as those of the thirteenthembodiment.

[0504] In the fourteenth embodiment, the backward movement camera 295may be provided on the head guard 296, not the rear portion of thevehicle body 281. Even such a structure can provide the same advantagesas those of the thirteenth embodiment.

[0505] In the twelfth embodiment, at the time the vehicle moves forward,an image in front of the forks 2 may be displayed small in a partialarea of the image in front of the vehicle, which is displayed on theentire display screen of the display device 28. Likewise, at the time ofa load carrying work, an image in front of the vehicle may be displayedsmall in a partial area of the image in front of the forks 2. In thiscase, the image pickup state of the camera can be monitored. The same isapplied to the fourteenth embodiment.

1. A load handling operation aiding apparatus in an industrial vehicle,which comprises: a load carrying apparatus which is movably provided ona vehicle body and is positioned to a load handling target according toits movement; display means; detection means for detecting a position ofthe load handling target; and display control means for displayingpositioning information for supporting positioning of said load carryingapparatus with respect to said load handling target on said displaymeans based on a position detection result detected by said detectionmeans.
 2. A load handling operation aiding apparatus in an industrialvehicle, which comprises: a load carrying apparatus movably provided ona vehicle body for doing a load carrying work; image pickup means forpicking up an image of a load handling target as a work target of saidload carrying apparatus; display means for displaying an image picked upby said image pickup means on a screen; detection means for detecting aposition of said load handling target in an image pickup area of saidimage pickup means; calculation means for calculating positioninginformation for positioning of said load carrying apparatus with respectto the load handling target based on position data detected by saiddetection means; and drawing control means for drawing said positioninginformation on the screen of said display means.
 3. A load handlingoperation aiding apparatus in an industrial vehicle, which comprises: aload carrying apparatus movably provided on a vehicle body for doing aload carrying work; image pickup means for picking up an image of a loadhandling target as a work target of said load carrying apparatus;display means for displaying an image picked up by said image pickupmeans on a screen; detection means for detecting a position of said loadhandling target on said screen by performing image processing on imagedata picked up by said image pickup means; calculation means forcalculating a position of a moving target point on the screen of saiddisplay means based on position data detected by said detection means atthe time of positioning of said load carrying apparatus with respect tothe load handling target; and drawing control means for drawingpositioning information for notifying the position of said moving targetpoint on the image on said screen.
 4. The load handling operation aidingapparatus in an industrial vehicle according to any one of claims 1 to3, wherein said positioning information is information on a positionalrelationship between said load carrying apparatus and load handlingtarget.
 5. The load handling operation aiding apparatus in an industrialvehicle according to claim 4, wherein said positioning informationexpresses a positional relationship between said load carrying apparatusand load handling target in characters.
 6. A load handling operationaiding apparatus in an industrial vehicle, which comprises: a loadcarrying apparatus movably provided on a vehicle body for doing a loadcarrying work; image pickup means for picking up an image of a loadhandling target as a work target of said load carrying apparatus;display means for displaying an image picked up by said image pickupmeans on a screen; detection means for detecting a position of said loadhandling target on said screen based on image data picked up by saidimage pickup means; calculation means for calculating a position of amoving target point on the screen of said display means based onposition data detected by said detection means at the time ofpositioning of said load carrying apparatus with respect to the loadhandling target; and drawing control means for drawing a mark for visualconfirmation of the position of said moving target point on the image onsaid screen.
 7. The load handling operation aiding apparatus in anindustrial vehicle according to any one of claims 2 to 6, wherein saiddetection means is comprised of image recognition means for carrying outimage recognition process to calculate the position of said loadhandling target on said screen based on data of an image picked up bysaid image pickup means.
 8. A load handling operation aiding apparatusin an industrial vehicle, which comprises: a load carrying apparatusmovably provided on a vehicle body for doing a load carrying work; imagepickup means for picking up an image of a load handling target as a worktarget of said load carrying apparatus; display means for displaying animage picked up by said image pickup means on a screen; calculationmeans for calculating a position of a moving target point of a mark,affixed to said load handling target, on the screen of said displaymeans at the time of positioning of said load carrying apparatus withrespect to the load handling target; and drawing control means fordrawing a mark for visual confirmation of said moving target point onthe image on said screen.
 9. The load handling operation aidingapparatus in an industrial vehicle according to any one of claims 2 to8, wherein operation means to be manually operated to move said loadcarrying apparatus and control means for controlling drive means formoving said load carrying apparatus in accordance with a manualoperation of said operation means are provided, and said calculationmeans calculates a moving target point on the screen of said displaymeans when said load carrying apparatus is moved by a manual operationof said operation means.
 10. The load handling operation aidingapparatus in an industrial vehicle according to any one of claims 2 to9, wherein said image pickup means is a camera which is providedliftable with respect to said load carrying apparatus, discriminationmeans for discriminating whether a load carrying work by said loadcarrying apparatus is a load pickup work or a load deposition work isprovided, lifting means for lifting said camera up and down is providedin such a way that said camera is moved and placed in a positionaccording to a type of the load carrying work discriminated by thatdiscrimination means with respect to said load carrying apparatus, and aplaced position of said camera at the time of the load deposition workis set to a position which does not interfere with image pickup of awork area by a load picked up by said load carrying apparatus.
 11. Theload handling operation aiding apparatus in an industrial vehicleaccording to any one of claims 2 to 10, wherein said industrial vehiclehas a mast and a carriage provided on said mast in a liftable manner,said load carrying apparatus is provided on said carriage, said imagepickup means is a camera which is fixed to said mast, wherein said loadcarrying apparatus is constructed in such a way that when said loadcarrying apparatus is lifted up and down in a range of a predeterminedheight or more, said carriage is moved on said mast while said loadcarrying apparatus and said camera keep a constant positionalrelationship at least in a height direction, height detection means fordetecting a height of said load carrying apparatus is provided, andwherein said drawing control means draws a mark for visual confirmationof said moving target point on the image on said screen based onpositional data of the moving target point calculated by saidcalculation means when the more detected by said height detection meansis equal to or higher than said predetermined height.
 12. A loadhandling operation aiding apparatus in an industrial vehicle on which acarriage having a load carrying apparatus is so provided as to beliftable along a mast provided on a vehicle body, which comprises: acamera provided on said mast in such a way as to be able to pick up animage of a work area of said load carrying apparatus; display means fordisplaying an image picked up by said camera on a screen; discriminationmeans for discriminating whether a load carrying work to be carried outby said load carrying apparatus is a load pickup work or a loaddeposition work; detection means for determining a load handling targetaccording to a type of the load carrying work discriminated by saiddiscrimination means and detecting a position of said load handlingtarget on the screen of said display means by performing imagerecognition processing on a positional detection object of said loadhandling target based on image data picked up by said camera;calculation means for calculating a position of a moving target point onthe screen of said display means at the time of positioning of said loadcarrying apparatus with respect to the load handling target; and drawingcontrol means for drawing a mark for visual confirmation of said movingtarget point on the screen of said display means on the image on saidscreen.
 13. The load handling operation aiding apparatus in anindustrial vehicle according to any one of claims 1 to 12, wherein saiddetection means detects a position of a load handling target differentlybetween a load pickup work and a load deposition work, and wherein saiddisplay means displays positional information according to the loadhandling target detected by said detection means.
 14. An industrialvehicle equipped with a load handling operation aiding apparatus as setforth in any one of claims 1 to
 13. 15. The load handling operationaiding apparatus in an industrial vehicle according to claim 11 or 12,wherein said mast is a telescopic type multi-level mast constructed tohave multi-level constituting members including an inner mast, said mastis protracted and retracted by sliding of those constituting membersincluding an inner mast, and said mast is not protracted unless saidload carrying apparatus is moved and positioned at a topmost stage ofthe inner mast in said constituting members, and said camera is fixed tosaid inner mast.
 16. The load handling operation aiding apparatus in anindustrial vehicle according to claim 15, wherein said camera is placedin a position equivalent to approximately a widthwise directional centerof said load carrying apparatus in a state where said camera is fixed tosaid inner mast.
 17. The load handling operation aiding apparatus in anindustrial vehicle according to any one of claims 1 to 12, characterizedin that said load handling target is affixed with a reference mark to bea reference for positioning, said calculation means calculates a movingtarget point of said reference mark on the screen of said display means,and said drawing control means draws a mark indicating said movingtarget point of said reference mark on the image on said screen.
 18. Theload handling operation aiding apparatus in an industrial vehicleaccording to claim 12, characterized in that said object to be subjectedto image recognition is a mark affixed to said load handling target andthat mark is used in calculating the position of the load handlingtarget.
 19. The load handling operation aiding apparatus in anindustrial vehicle according to any one of claims 7 to 13 and 18,wherein said image recognition means calculates a position of a mark ofsaid load handling target on the screen of said display means based onimage data of said mark, said calculation means calculates a movingtarget point of said mark on the screen of said display means at thetime of positioning said load carrying apparatus to the load handlingtarget based on positional data of said mark calculated by said imagerecognition means, and said drawing control means draws a markindicating said moving target point of said mark on the image on saidscreen.
 20. The load handling operation aiding apparatus in anindustrial vehicle according to any one of claims 1 to 13 and 15 to 19,wherein said mark is constituted by a figure of a point target withrespect to a center point and said mark is drawn in such a way that saidcenter point coincides with said moving target point.
 21. The loadhandling operation aiding apparatus in an industrial vehicle accordingto any one of claims 1 to 13 and 15 to 20, characterized in that saidload handling target is a pallet or a shelf portion.
 22. A load handlingcontrol apparatus in an industrial vehicle, which comprises: a loadcarrying apparatus which is provided in a displaceable manner on avehicle body of the industrial vehicle for doing a load carrying work;load detection means for detecting whether or not there is a load placedon or held by the load carrying apparatus and outputting a detectionsignal; decision means for determining whether the load carrying work isa load pickup work or a load deposition work based on the detectionsignal from said load detection means; and control means for causingsaid load carrying apparatus to do a load pickup work or a loaddeposition work based on decision by said decision means.
 23. A loadhandling control apparatus in an industrial vehicle, which comprises: aload carrying apparatus which is provided in a displaceable manner on avehicle body of the industrial vehicle for doing a load carrying work;load detection means for detecting whether or not there is a load placedon or held by the load carrying apparatus and outputting a detectionsignal; at least one actuator to be driven to cause said load carryingapparatus to do the load carrying work; decision means for determiningthe type of said load carrying work based on the detection signal fromsaid load detection means; and control means for driving said actuatorin accordance with the type of the load carrying work determined by saiddecision means.
 24. The load handling control apparatus in an industrialvehicle according to claim 23, characterized in that said load carryingapparatus is liftable up and down along a mast provided on the vehiclebody, said actuator is driven to lift said load carrying apparatus upand down along the mast, and said load carrying apparatus is lifted upto a load pickup height by said actuator when it is determined by saiddecision means that the type of the load carrying work is a load pickupwork, and said load carrying apparatus is lifted up to a load depositionheight by said actuator when it is determined by said decision meansthat the type of the load carrying work is a load deposition work. 25.The load handling control apparatus in an industrial vehicle accordingto claim 23 or 24, characterized in that said decision means determinesthat the type of the load carrying work is a load deposition work whenit is detected that there is a load on said load carrying apparatus, andsaid decision means determines that the type of the load carrying workis a load pickup work when it is detected that there is no load on saidload carrying apparatus.
 26. The load handling control apparatus in anindustrial vehicle according to any one of claims 23 to 25,characterized in that start operation means for outputting an operationsignal at the time of starting automatic load handling control of saidload carrying apparatus is used commonly in a plurality of differentload carrying works, and said control means performs automatic loadhandling control of said load carrying apparatus by driving saidactuator in accordance with the type of the load carrying workdetermined by said decision means when an operation signal is input fromsaid operation means.
 27. The load handling control apparatus in anindustrial vehicle according to any one of claims 23 to 25,characterized in that detection means outputs a signal to be used indetermining if a start condition to start automatic load handlingcontrol of said load carrying apparatus is satisfied, and when receivingthe signal of the start condition being met from said detection means,said control means performs said automatic load handling control bydriving said actuator in accordance with the type of the load carryingwork determined by said decision means.
 28. The load handling controlapparatus in an industrial vehicle according to claim 26 or 27,characterized in that said automatic load handling control is control toposition said load carrying apparatus with respect to the load handlingtarget, said control means controls said actuator to place said loadcarrying apparatus in a work start position set in accordance with thetype of the load carrying work determined by said decision means.
 29. Aload handling control apparatus in an industrial vehicle, whichcomprises: a load carrying apparatus which is provided in a displaceablemanner on a vehicle body of the industrial vehicle for doing a loadcarrying work; load detection means for detecting whether or not thereis a load placed on or held by the load carrying apparatus andoutputting a detection signal; an aiding apparatus provided to supportan automatic load control of the handling work of said load carryingapparatus and equipped with at least one actuator; decision means fordetermining the type of said load carrying work based on the detectionsignal from said load detection means; and control means for controllingsaid actuator in accordance with the type of the load carrying workdetermined by said decision means.
 30. The load handling controlapparatus in an industrial vehicle according to claim 29, wherein startoperation means for outputting an operation signal at the time ofstarting automatic load handling control of said load carrying apparatusis used commonly in a plurality of different load carrying works, andsaid control means supports said automatic load handling control bydriving said actuator in accordance with the type of the load carryingwork determined by said decision means.
 31. The load handling controlapparatus in an industrial vehicle according to claim 29, whereindetection means outputs a signal to be used in determining if a startcondition to start a support operation to support automatic loadhandling control of said load carrying apparatus is satisfied, and whenreceiving the signal of the start condition being met from saiddetection means, said control means supports said automatic loadhandling control by driving and controlling said actuator with a controlcontent according to the type of the load carrying work determined bysaid decision means.
 32. The load handling control apparatus in anindustrial vehicle according to any one of claims 23 and 26 to 31,wherein types of said load carrying works include a load deposition workand a load pickup work.
 33. The load handling control apparatus in anindustrial vehicle according to claim 22 or 23, further having imagepickup means for picking up an image of a sign for positional detectionprovided on a load handling target and image processing means fordetecting a position of said load handling target by performingpredetermined image processing on the image picked up by said imagepickup means, and wherein said control means lifts said load carryingapparatus up or down to a load pickup height estimated from the positionof the load handling target detected by said image processing means whenit is determined by said decision means that said load carrying work isa load pickup work, and lifts said load carrying apparatus up or down toa load deposition height estimated from the position of the loadhandling target detected by said image processing means when it isdetermined by said decision means that said load carrying work is a loaddeposition work.
 34. The load handling control apparatus in anindustrial vehicle according to claim 22 or 23, wherein the industrialvehicle has start operation means for automatic elevation and anautomatic elevation unit for lifting the load carrying apparatus up to apredetermined height by an operation signal from said start operationmeans, said control means drives the actuator for automatic elevationcontrol of the load carrying apparatus by said automatic elevation unit,and when elevation is designated by the operation signal from said startoperation means, said control means positions said load carryingapparatus in either a load deposition position or a load pickup positiondetermined according to the type of the load carrying work determined bysaid decision means with respect to the height instructed by saidoperation signal.
 35. An industrial vehicle equipped with a loadhandling control apparatus as set forth in any one of claims 22 to 34.36. The load handling control apparatus in an industrial vehicleaccording to any one of claims 22 to 34, wherein said load detectionmeans is load weight detection means for detecting a value according toa weight of a load placed on or held by the load carrying apparatusprovided on the industrial vehicle, and said decision means determinesthe type of the load carrying work based on a detected value detected bysaid load weight detection means.
 37. The load handling controlapparatus in an industrial vehicle according to any one of claims 22 to34, wherein said load detection means is load weight detection means fordetecting a value according to a weight of a load placed on or held bythe load carrying apparatus provided on the industrial vehicle, and saiddecision means determines that the load carrying work is a load pickupwork when a detected value detected by said load weight detection meansis equal to or smaller than a preset threshold value and determines thatthe load carrying work is a load deposition work when said detectedvalue exceeds said threshold value.
 38. The load handling controlapparatus in an industrial vehicle according to any one of claims 22 to28 and 32 to 34, wherein said control means performs positioning controlto position the load carrying apparatus with respect to the loadhandling target according to the type of the load carrying work.
 39. Theload handling control apparatus in an industrial vehicle according toany one of claims 22 to 28 and 32 to 34, wherein said control meansstarts control to automatically execute a load pickup work or a loaddeposition work before completion of load pickup or load deposition, ora load pickup work or a load deposition work after completion of loadpickup or load deposition based on an operation signal from startoperation means, and controls actuation of at least one actuatorprovided to operate said load carrying apparatus.
 40. The load handlingcontrol apparatus in an industrial vehicle according to any one ofclaims 22 to 28 and 32 to 34, wherein said control means controlsactuation of at least one actuator provided to operate said loadcarrying apparatus and said control means starts control toautomatically execute a load pickup work or a load deposition work untilload pickup or load deposition is completed, based on an operationsignal from start operation means.
 41. The load handling controlapparatus in an industrial vehicle according to any one of claims 22 to34, 36 and 38 to 40, wherein said decision means determines that theload carrying work is a load pickup work when a signal output from saidload detection means is a signal indicating no load and determines thatthe load carrying work is a load deposition work when the signalindicates presence of a load.
 42. A work mode switching apparatus for anindustrial vehicle, which industrial vehicle can do a predetermined workunder automatic control and which work mode switching apparatus canselectively set one work mode selected from a plurality of work modesfor that predetermined work, comprising: detection means for detecting astate of said predetermined work at the time of doing that work underautomatic control; work mode setting means for selectively setting onework mode from said plurality of work modes according to contents ofsaid predetermined work based on a detected value from said detectionmeans; and switching means for manually switching said work mode set bysaid work mode setting means to another work mode.
 43. The work modeswitching apparatus in an industrial vehicle according to claim 42,wherein notification means for notifying a work mode set by said workmode setting means is provided.
 44. The work mode switching apparatus inan industrial vehicle according to claim 42 or 43, wherein saidindustrial vehicle has an attachment for doing a load carrying work,said detection means comprises of load weight detection means fordetecting a load weight applied to said attachment, and said work modesinclude a load pickup mode for picking up a load with the attachment anda load deposition mode for placing a load in a predetermined positionwith the attachment, and said mode setting means sets said work mode toone of the load pickup mode and the load deposition mode based on theload weight obtained from a detection result from said load weightdetection means.
 45. The work mode switching apparatus in an industrialvehicle according to claim 44, wherein said work mode setting meansselectively sets a single work mode from said plurality of work modes atthe time of positioning said attachment.
 46. The work mode switchingapparatus in an industrial vehicle according to any one of claims 42 to45, wherein said industrial vehicle has a load handling lever to beoperated at the time of a load carrying work and said switching means isprovided on said load handling lever.
 47. The work mode switchingapparatus in an industrial vehicle according to any one of claims 43 to46, wherein said notification means is display means for visuallynotifying a work mode set by said work mode setting means.
 48. The workmode switching apparatus in an industrial vehicle according to any oneof claims 44 to 47, comprising: at least one actuator to be driven tomove said attachment; image pickup means for picking up a working stateof said load carrying work; sign-position calculation means forperforming image recognition processing on a sign for detection of aposition determined in accordance with the work mode set by said workmode setting means or switching means based on image data acquired bysaid image pickup means to thereby calculate a coordinate position ofsaid sign in screen coordinates; moving distance calculation means forcalculating a coordinate position of said attachment in real coordinatesbased on a result of calculation by said sign position calculation meansto thereby calculate a distance of said attachment to be moved withrespect to a target position; and control means for driving saidactuator to move said attachment by the distance calculated by saidmoving distance calculation means in such a way that said attachment isplaced in said target position.
 49. The work mode switching apparatus inan industrial vehicle according to any one of claims 44 to 47,comprising: at least one actuator to be driven to move said attachment;start operation means to be operated to start a load carrying work andfor designating a height position of the attachment; an automaticelevation unit for lifting said attachment up to the height positiondesignated by an operation signal from that start operation means; andcontrol means for driving said actuator to move said attachment to apredetermined height determined from the operation signal from saidstart operation means and the work mode set by said work mode settingmeans or switching means.
 50. An industrial vehicle equipped with a workmode switching apparatus as set forth in any one of claims 42 to
 49. 51.The work mode switching apparatus in an industrial vehicle according toany one of claims 44 to 47, wherein at least one actuator to be drivento move said attachment and control means for controlling said actuatorare provided.
 52. The work mode switching apparatus in an industrialvehicle according to any one of claims 46 to 49, wherein said loadhandling lever is a lift lever to be operated to lift said attachment upand down.
 53. A load handling aiding notification apparatus in anindustrial vehicle in an industrial vehicle, which comprises: a loadcarrying apparatus movably provided on a vehicle body for doing a loadcarrying work; detection means for detecting a position of a loadhandling target before the vehicle approaches said load handling target;calculation means for calculating a positional relationship between saidload handling target and vehicle based on a result of detection by saiddetection means; and notification means for notifying steeringinformation for guiding the vehicle in such a way that said loadhandling target is caught by said load carrying apparatus based on aresult of calculation by said calculation means.
 54. The load handlingaiding notification apparatus in an industrial vehicle according toclaim 53, wherein said steering information includes a direction of thevehicle.
 55. The load handling aiding notification apparatus in anindustrial vehicle according to claim 54, wherein said direction of thevehicle is a pull-over direction.
 56. The load handling aidingnotification apparatus in an industrial vehicle according to claim 55,wherein the positional relationship between said load handling targetand said vehicle includes a pull-over direction and pull-over distanceof the vehicle that are necessary for catching said load handling targetby said load carrying apparatus, and said notification means notifiessteering information, which includes the pull-over direction andpull-over distance of said vehicle based on the positional relationshipcalculated by said calculation means.
 57. The load handling aidingnotification apparatus in an industrial vehicle according to any one ofclaims 53 to 56, wherein decision means for determining whether or notthe load handling target can be caught by the load carrying apparatuswhen the vehicle is moved in a current steering state is provided, andwherein said notification means notifies said steering information whensaid decision means has determined that the load handling target cannotbe caught by the load carrying apparatus.
 58. The load handling aidingnotification apparatus in an industrial vehicle according to any one ofclaims 53 to 57, wherein said load carrying apparatus is providedmovable in a vehicle's widthwise direction with respect to a vehiclebody, and said load carrying apparatus catching said load handlingtarget means that said load handling target is caught in a moving rangeof said load carrying apparatus in the vehicle's widthwise direction.59. The load handling aiding notification apparatus in an industrialvehicle according to claim 58, wherein, when it is determined, based onthe result of calculation by said calculation means, that said loadcarrying apparatus can catch said load target without moving in thevehicle's widthwise direction, said notification means notifies steeringinformation of that effect.
 60. The load handling aiding notificationapparatus in an industrial vehicle according to any one of claims 1 to7, wherein said detection means has image pickup means for picking up animage of a load handling target and image recognition means forcalculating a position of said load handling target by performing imagerecognition of a mark provided on said load handling target based onimage data picked up by said image pickup means, and said notificationmeans has display means for displaying an image picked up by said imagepickup means and said display means displays said steering informationon said screen.
 61. The load handling aiding notification apparatus inan industrial vehicle according to claim 60, wherein said calculationmeans has display position determining means for determining a displayposition of steering information on said screen in such a way as toavoid blocking said image displayed on said screen by said displaymeans, and said notification means displays said steering information inthe display position of said screen determined by said display positiondetermining means.
 62. The load handling aiding notification apparatusin an industrial vehicle according to any one of claims 53 to 59,wherein said notification means has display means and displays saidsteering information based on the result of calculation by saidcalculation means on a screen of said display means.
 63. The loadhandling aiding notification apparatus in an industrial vehicleaccording to any one of claims 53 to 62, wherein said notification meanshas voice notification means which notifies said steering informationwith sounds.
 64. A load handling aiding notification apparatus in anindustrial vehicle, which comprises: a load carrying apparatus providedmovable at least in a forward and backward direction on a vehicle bodyfor doing a load carrying work; detection means for detecting a positionof a load handling target before the vehicle approaches said loadhandling target; calculation means for calculating a positionalrelationship between said load handling target and vehicle based on aresult of detection by said detection means; and notification means fornotifying a position to which the vehicle is to approach, based on aresult of calculation by said calculation means, in such a way that saidload handling target is caught in a moving range of said load carryingapparatus in the forward and backward direction.
 65. A load handlingaiding notification apparatus in an industrial vehicle, which comprises:a load carrying apparatus provided movable at least in a forward andbackward direction on a vehicle body for doing a load carrying work;detection means for detecting a position of a load handling target;calculation means for calculating a positional relationship between saidload handling target and vehicle based on a result of detection by saiddetection means; and notification means for instructing a position towhich said load carrying apparatus is to be moved forward, based on aresult of calculation by said calculation means.
 66. A load handlingaiding notification apparatus in an industrial vehicle, which comprises:a load carrying apparatus movably provided on a vehicle body for doing aload carrying work; detection means for detecting a position of a loadhandling target beforehand before the vehicle approaches said loadhandling target; calculation means for calculating a positionalrelationship between said load handling target and said vehicle based ona result of detection by said detection means; decision means fordetermining, based on a result of calculation by said calculation means,whether or not said load handling target can be caught in a moving rangeof said load carrying apparatus; and notification means for notifying aresult of decision by said decision means.
 67. A load handling aidingnotification apparatus in an industrial vehicle, which comprises: a loadcarrying apparatus provided movable at least in an up and down directionon a vehicle body for doing a load carrying work; detection means fordetecting a height of a load handling target beforehand before thevehicle approaches said load handling target; decision means fordetermining whether or not said load carrying apparatus can be lifted upto a height to reach said load handling target; and notification meansfor notifying a result of decision by said decision means.
 68. Anindustrial vehicle equipped with a load handling aiding notificationapparatus as set forth in any one of claims 53 to
 67. 69. The loadhandling aiding notification apparatus according to claim 53, whereinsaid detection means detects the position of a load handling targetbefore the vehicle approaches the load handling target to be able to doa load carrying work for said load handling target.
 70. The loadhandling aiding notification apparatus in an industrial vehicleaccording to claim 61, wherein the positional relationship between saidload handling target and said vehicle includes a pull-over direction andpull-over distance of the vehicle, which are necessary for catching saidload handling target by said load carrying apparatus, and said displayposition determining means determines the display position of thesteering information to be leftward on the screen when said pull-overdirection is a rightward direction and determines the display positionof the steering information to be rightward on the screen when saidpull-over direction is a leftward direction.
 71. The load handlingaiding notification apparatus in an industrial vehicle according to anyone of claims 64 to 67, wherein said detection means has image pickupmeans for picking up an image of a load handling target and imagerecognition means for calculating a position of said load handlingtarget by performing image recognition of a mark provided on said loadhandling target based on image data picked up by said image pickupmeans, and said notification means has display means for displaying animage picked up by said image pickup means and displays saidnotification content on a screen of said display means.
 72. The loadhandling aiding notification apparatus in an industrial vehicleaccording to claim 71, wherein said calculation means has displayposition determining means for determining a display position fordisplaying said notification content while avoiding said load handlingtarget on the screen of said display means, and said notification meansdisplays said notification content in said display position on thescreen of said display means.
 73. The load handling aiding notificationapparatus in an industrial vehicle according to any one of claims 64 to67, wherein said notification means has display means and displays saidnotification content based on said calculation result on the screen ofsaid display means.
 74. The load handling aiding notification apparatusin an industrial vehicle according to any one of claims 64 to 67,wherein said notification means has voice notification means whichnotifies said notification content with sounds.
 75. The load handlingaiding notification apparatus in an industrial vehicle according to anyone of claims 53 to 68, wherein said load handling target includes apallet and a rack.
 76. A voice notification apparatus for an industrialvehicle, which comprises: a load carrying apparatus movably provided ona vehicle body for doing a load carrying work; image pickup means forpicking up an image of a load handling target at the time of a loadhandling operation by said load carrying apparatus; identification meansfor identifying a sign to be a mark at the time of positioning said loadcarrying apparatus based on image data picked up by said image pickupmeans; detection means for detecting a position of said load carryingapparatus with respect to said sign based on a result of identificationby said identification means; display means for visually displaying theposition of said load carrying apparatus based on a result of detectionby said detection means; output means capable of outputting voices to adriver; and voice synthesizing means for, when a display state by saiddisplay means is changed according to a change in the position of saidload carrying apparatus with respect to the sign, causing said outputmeans to output sounds according to that change.
 77. The voicenotification apparatus in an industrial vehicle according to claim 76,wherein calculation means for calculating a moving target point of saidsign on a screen of said display means at a time of positioning saidload carrying apparatus is provided, and when a positional relationshipbetween said sign on the screen of said display means and said movingtarget point changes, said voice synthesizing means causes said outputmeans to make notification to that effect.
 78. The voice notificationapparatus in an industrial vehicle according to claim 77, wherein whensaid moving target point on the screen of said display means coincideswith said sign, said voice synthesizing means makes notification to thateffect.
 79. The voice notification apparatus in an industrial vehicleaccording to claim 77, wherein when said moving target point on thescreen of said display means comes off said sign, said voicesynthesizing means makes notification to that effect.
 80. The voicenotification apparatus in an industrial vehicle according to claim 76,wherein when said image pickup means catches said sign and saididentification means identifies the sign and said sign is displayed onthe screen of said display means, said voice synthesizing means makesnotification to that effect.
 81. The voice notification apparatus in anindustrial vehicle according to claim 76, wherein when said sign ispositioned outside an image pickup range of said image pickup means andsaid identification means does not identify the sign and said sign comesoff the screen of said display means, said voice synthesizing meansmakes notification to that effect.
 82. The voice notification apparatusin an industrial vehicle according to any one of claims 78 to 81,wherein said voice synthesizing means makes notification of at least twoof four notifications when said moving target point coincides with saidsign on the screen of said display means, when said moving target pointcomes off said sign, when said sign is displayed, and when said signcomes off.
 83. The voice notification apparatus in an industrial vehicleaccording to any one of claims 76 to 82, wherein measuring means formeasuring remaining battery power of a battery is provided, and whensaid remaining battery power measured by said measuring means becomesequal to or smaller than a predetermined threshold value, said voicesynthesizing means makes notification to that effect.
 84. The voicenotification apparatus in an industrial vehicle according to any one ofclaims 76 to 83, wherein a position control system for detecting apositional relationship between said sign and said load carryingapparatus by performing image recognition processing is provided, and ata time said position control system is activated, said voicesynthesizing means makes notification to that effect.
 85. A voicenotification apparatus for an industrial vehicle equipped with operationmeans to be manually operated to move a load carrying apparatus fordoing a load carrying work, which comprises: display means capable ofdisplaying a state of said load carrying apparatus in a plurality ofdifferent display modes; a plurality of output means capable ofgenerating sounds in a plurality of different modes; detection means fordetecting the state of said load carrying apparatus for aiding the loadcarrying work; display control means for determining whether said loadcarrying apparatus is in a state matched with a target normal state orin a state deviated therefrom based on a result of detection by saiddetection means and displaying a determination result on said displaymeans in different display modes according to said determination result;and voice synthesizing means for determining based on the result ofdetection by said detection means whether or not said load carryingapparatus has had a state change between said normal state and saiddeviated-from-normal state and causing said output means to generatesounds in different modes according to a type of that state change whenthere has been said state change.
 86. An industrial vehicle equippedwith a voice notification apparatus as set forth in any one of claims 76to
 85. 87. The voice notification apparatus in an industrial vehicleaccording to any one of claims 76 to 85, having at least one actuator tobe driven to move said load carrying apparatus, positional informationdetection means for detecting positional information on screencoordinates of said sign based on an identification result from saididentification means, calculation means for calculating a position ofsaid load carrying apparatus on real coordinates based on a result ofdetection by said positional information detection means and calculatinga distance to move said load carrying apparatus with respect to a targetposition, and control means for driving said actuator to move said loadcarrying apparatus by the distance calculated by said calculation meansin order to move said load carrying apparatus to said target position.88. The voice notification apparatus in an industrial vehicle accordingto any one of claims 76 to 85, having drawing display means for drawingsaid moving target point on the screen of said display means.
 89. A workview field aiding apparatus in an industrial vehicle for an industrialvehicle capable of doing a plurality of different works, which picks upa work image that supports a work view field of a driver at a time ofdoing each work by a camera provided for each work and shows the driverthat work image according to each work.
 90. A work view field aidingapparatus for an industrial vehicle capable of doing a plurality ofdifferent works, which picks up a work image that supports a work viewfield of a driver at the time of doing each work by a camera providedfor each work, with a camera provided for each work, and shows thedriver that work image according to each work.
 91. A work view fieldaiding apparatus for an industrial vehicle capable of doing a pluralityof different works, which comprises: a plurality of cameras for pickingup work images that support a work view field of a driver at a time ofdoing individual works; work image display means for showing the driverthat work image, which is picked up by each camera; and display controlmeans for controlling said work image display means to display a workimage for each work on said work image display means.
 92. The work viewfield aiding apparatus in an industrial vehicle according to claim 91,wherein said works are a load carrying work for operating a loadcarrying apparatus of the vehicle and a moving work for running thevehicle, said cameras are a camera for load handling for picking up awork image for said load carrying work and a camera for driving forpicking up a work image for said moving work, said display control meanscomprises: work discrimination means for discriminating if a work is oneof said load carrying work and moving work; and display switching meansfor displaying the work image for said load carrying work when thediscriminated work is the load carrying work and displaying the workimage for said moving work when the discriminated work is the movingwork.
 93. The work view field aiding apparatus in an industrial vehicleaccording to claim 92, wherein said industrial vehicle is a forklifttruck, and said camera for load handling is provided on forks providedon a mast as said load carrying apparatus or on a lifting member whichlifts up and down together with the forks, and picks up an image infront of the forks as a work image.
 94. The work view field aidingapparatus in an industrial vehicle according to claim 93, wherein saidwork discrimination means has height detection means for detecting if aheight position of said forks is equal to or lower than a presetreference height position, and wherein said display switching meansdisplays the work image for said moving work when the detected heightposition is equal to or lower than said reference height position ordisplays the work image for said load carrying work when it exceeds saidreference height position.
 95. The work view field aiding apparatus inan industrial vehicle according to claim 93 or 94, having positioncontrol means for acquiring a positional deviation amount of a loadhandling target with respect to said camera for load handling from theimage in front of said forks picked up by said camera and adjusting aposition of the forks in such a way as to cancel out that positionaldeviation amount.
 96. The work view field aiding apparatus in anindustrial vehicle according to any one of claims 92 to 95, wherein saidcamera for drive picks up an image in front of the vehicle as a workimage.
 97. The work view field aiding apparatus in an industrial vehicleaccording to any one of claims 92 to 95, wherein said camera for drivepicks up a rearward image of the vehicle as a work image.
 98. A workview field aiding apparatus for an industrial vehicle capable of doing aplurality of different works, which is equipped with a single workcamera for picking up a work image that supports a work view field of adriver at a time of doing each work in said plurality of differentworks, wherein said work view field aiding apparatus switches an imagepickup direction of that work camera to a direction for picking up awork image for said work to be done, and said work view field aidingapparatus shows a work image to be picked up by the work camera to thedriver after switching.
 99. A work view field aiding apparatus for anindustrial vehicle capable of dong a plurality of different works, saidwork view field aiding apparatus comprising: a single work camera forpicking up a work image that supports a work view field of a driver whodoes each work in said plurality of different works; image pickupdirection switching means for switching an image pickup direction ofsaid work camera to a direction for picking up a work image for saidwork; and image display means for showing to the driver said work imageto be picked up by said work camera.
 100. The work view field aidingapparatus in an industrial vehicle according to claim 99, wherein saidworks are a load carrying work for operating a load carrying apparatusof the vehicle and a moving work for running the vehicle, and whereinsaid image pickup direction switching means has: state adjusting meansfor switching and adjusting the image pickup direction of said workcamera; work discrimination means for discriminating if a work is one ofsaid load carrying work and moving work; and switching control means forcontrolling said state adjusting means based on a discrimination resultfrom said work discrimination means and the image pickup direction ofsaid work camera is set to a direction for picking up a work image forthe load carrying work when the discriminated work is the load carryingwork or the image pickup direction of said work camera is set to adirection for picking up a work image for the moving work when thediscriminated work is the moving work.
 101. The work view field aidingapparatus in an industrial vehicle according to claim 100, wherein saidindustrial vehicle is a forklift truck, said load carrying apparatus isa full free mast, said work camera is provided on its inner mast, saidwork discrimination means is height detection means for detecting if aheight position of said forks is equal to or lower than a presetreference height position, and said switching control means sets theimage pickup direction of said work camera to a direction for picking upan image in front of the vehicle as a work image when the heightposition is equal to or lower than said reference height position, orsets the image pickup direction of said work camera to a direction forpicking up an image in front of the forks as a work image when theheight position exceeds the reference height position.
 102. The workview field aiding apparatus in an industrial vehicle according to claim101, having position control means for acquiring a positional deviationamount of a load handling target with respect to the camera for loadhandling from the image in front of said forks picked up by said cameraand adjusting a position of the forks in such a way as to cancel outthat positional deviation amount.
 103. An industrial vehicle equippedwith a work view field aiding apparatus as set forth in any one ofclaims 89 to
 102. 104. The work view field aiding apparatus in anindustrial vehicle according to any one of claims 91 to 97, wherein saidwork image display means has a display device, provided in a driver'sseat of the vehicle, for showing a work image to the driver.
 105. Thework view field aiding apparatus in an industrial vehicle according toclaim 104, wherein said work image display means displays a work imageat that time on an entire display screen of said display device anddisplays, on a part of that work image, another work image.
 106. Thework view field aiding apparatus in an industrial vehicle according toclaim 92, wherein said camera for load handling is provided on a movableportion of said load carrying apparatus.
 107. The work view field aidingapparatus in an industrial vehicle according to any one of claims 99 to102, wherein said image display means has a display device, provided ina driver's seat of the vehicle, for showing a work image to the driver.